The current usb device g-tx-fifo-size setting in DT causes two problems
for kernel driver.

1. On hi6220, there are 15 tx_fifo dedicated for all EPs except EP0,
   while DT only provides tx_fifo settings for 6 EPs.  It results in the
   following annoying complaints from kernel.

[    4.451623] dwc2 f72c0000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[7]=0
[    4.461303] dwc2 f72c0000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[8]=0
[    4.470969] dwc2 f72c0000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[9]=0
[    4.480632] dwc2 f72c0000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[10]=0
[    4.490385] dwc2 f72c0000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[11]=0
[    4.500140] dwc2 f72c0000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[12]=0
[    4.509892] dwc2 f72c0000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[13]=0
[    4.519646] dwc2 f72c0000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[14]=0
[    4.529399] dwc2 f72c0000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[15]=0
[    4.539244] dwc2 f72c0000.usb: EPs: 16, dedicated fifos, 1920 entries in SPRAM

   Besides of that, the total 1920 fifo entries isn't fully utilized.
   Endpoint Info Control block consumes 128 entries, g-rx-fifo-size
   is 512, and g-np-tx-fifo-size is 128.  So the fifi entries available
   for tx_fifo is: 1920 - 128 - 512 - 128 = 1152.  Considering that
   the minimal valid tx_fifo size for each EP is 16, it should be
   reasonable to allocate 1152 entries as: 128 x 8 + 16 x 7 = 1136 (only
   16 entries unused).  With this new setting, we can get more EPs to
   use while removing the above warning messages in the meantime.

2. Another consequence of above invalid g_tx_fifo_size parameter is that
   kernel driver will use values read from hardware register as the
   fall-back.  The value is 2048 for each EP fifo.  That's obviously
   invalid either, because even fifo entries for one EP exceeds the
   total entries 1920.  That's why we see the following fat warning from
   function dwc2_hsotg_init_fifo().  The new g-tx-fifo-size settings
   help to remove the warning as well.

[   65.431634] dwc2 f72c0000.usb: Do port resume before switching to device mode
[   65.624176] insufficient fifo memory
[   65.624369] ------------[ cut here ]------------
[   65.633633] WARNING: CPU: 0 PID: 5 at drivers/usb/dwc2/gadget.c:330 dwc2_hsotg_init_fifo+0x164/0x1ac
[   65.643808] CPU: 0 PID: 5 Comm: kworker/u16:0 Not tainted 4.13.0-rc1-00022-g50861cf9dc1b-dirty #81
[   65.653769] Hardware name: HiKey Development Board (DT)
[   65.659624] Workqueue: dwc2 dwc2_conn_id_status_change
[   65.665377] task: ffffffc005f73400 task.stack: ffffffc005f98000
[   65.671987] PC is at dwc2_hsotg_init_fifo+0x164/0x1ac
[   65.677633] LR is at dwc2_hsotg_init_fifo+0x164/0x1ac
[   65.683275] pc : [<ffffff8008638044>] lr : [<ffffff8008638044>] pstate: 600001c5
[   65.691504] sp : ffffffc005f9bce0
[   65.695218] x29: ffffffc005f9bce0 x28: ffffffc005f6ac00
[   65.701172] x27: ffffffc005f73400 x26: 0000000008000580
[   65.707124] x25: ffffff8008bb4af0 x24: ffffff8008d02b70
[   65.713074] x23: 0000003fcc831084 x22: ffffffc0337cf0bc
[   65.719024] x21: 0000000000000580 x20: ffffffc0337cf018
[   65.724976] x19: ffffffc0337cf098 x18: 0000000000000000
[   65.730926] x17: 0000000000000000 x16: 0000000000000000
[   65.736873] x15: 0000000000000000 x14: ffffff8008ca8900
[   65.742825] x13: 0000004035299000 x12: 0000000034d5d91d
[   65.748775] x11: 0000000000000000 x10: 00000000000008d0
[   65.754726] x9 : ffffffc005f9bce0 x8 : 00000000000001b5
[   65.760674] x7 : 66696620746e6569 x6 : ffffff8008d60050
[   65.766623] x5 : 0000000000000000 x4 : 0000000000000000
[   65.772573] x3 : 0000000000000002 x2 : 0000000000000002
[   65.778521] x1 : 0000000000000001 x0 : 0000000000000018
[   65.784469] Call trace:
[   65.787236] Exception stack(0xffffffc005f9bb10 to 0xffffffc005f9bc40)
[   65.794420] bb00:                                   ffffffc0337cf098 0000008000000000
[   65.803145] bb20: ffffffc005f9bce0 ffffff8008638044 ffffff8008bb4af0 0000000008000580
[   65.811870] bb40: ffffffc005f73400 ffffffc005f6ac00 0000000000000000 ffffff8008da2998
[   65.820595] bb60: ffffffc005f9bce0 ffffffc005f9bce0 ffffffc005f9bca0 00000000ffffffc8
[   65.829315] bb80: ffffffc005f9bbb0 ffffff80081046a0 ffffffc005f9bce0 ffffffc005f9bce0
[   65.838038] bba0: ffffffc005f9bca0 00000000ffffffc8 0000000000000018 0000000000000001
[   65.846761] bbc0: 0000000000000002 0000000000000002 0000000000000000 0000000000000000
[   65.855485] bbe0: ffffff8008d60050 66696620746e6569 00000000000001b5 ffffffc005f9bce0
[   65.864207] bc00: 00000000000008d0 0000000000000000 0000000034d5d91d 0000004035299000
[   65.872928] bc20: ffffff8008ca8900 0000000000000000 0000000000000000 0000000000000000
[   65.900856] [<ffffff8008638044>] dwc2_hsotg_init_fifo+0x164/0x1ac
[   65.927195] [<ffffff800863b390>] dwc2_hsotg_core_init_disconnected+0x80/0x3c0
[   65.954736] [<ffffff800862fef0>] dwc2_conn_id_status_change+0xfc/0x21c
[   65.981561] [<ffffff80080d1ca8>] process_one_work+0x124/0x294
[   66.007419] [<ffffff80080d1e70>] worker_thread+0x58/0x3c8
[   66.023243] [<ffffff80080d79a0>] kthread+0x100/0x12c
[   66.032455] [<ffffff8008082ec0>] ret_from_fork+0x10/0x50
[   66.041987] ---[ end trace 7079dcaa2d9e46fa ]---
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>