usb: dwc3: gadget: Fix system suspend/resume on TI platforms

On TI platforms (dra7, am437x), the DWC3_DSTS_DEVCTRLHLT bit is not set
after the device controller is stopped via DWC3_DCTL_RUN_STOP.

If we don't disconnect and stop the gadget, it stops working after a
system resume with the trace below.

There is no point in preventing gadget disconnect and gadget stop during
system suspend/resume as we're going to suspend in any case, whether
DEVCTRLHLT timed out or not.

[  141.727480] ------------[ cut here ]------------
[  141.732349] WARNING: CPU: 1 PID: 2135 at drivers/usb/dwc3/gadget.c:2384 dwc3_stop_active_transfer.constprop.4+0xc4/0xe4 [dwc3]
[  141.744299] Modules linked in: usb_f_ss_lb g_zero libcomposite xhci_plat_hcd xhci_hcd usbcore dwc3 evdev udc_core m25p80 usb_common spi_nor snd_soc_davinci_mcasp snd_soc_simple_card snd_soc_edma snd_soc_tlv3e
[  141.792163] CPU: 1 PID: 2135 Comm: irq/456-dwc3 Not tainted 4.10.0-rc8 #1138
[  141.799547] Hardware name: Generic DRA74X (Flattened Device Tree)
[  141.805940] [<c01101b4>] (unwind_backtrace) from [<c010c31c>] (show_stack+0x10/0x14)
[  141.814066] [<c010c31c>] (show_stack) from [<c04a0918>] (dump_stack+0xac/0xe0)
[  141.821648] [<c04a0918>] (dump_stack) from [<c013708c>] (__warn+0xd8/0x104)
[  141.828955] [<c013708c>] (__warn) from [<c0137164>] (warn_slowpath_null+0x20/0x28)
[  141.836902] [<c0137164>] (warn_slowpath_null) from [<bf27784c>] (dwc3_stop_active_transfer.constprop.4+0xc4/0xe4 [dwc3])
[  141.848329] [<bf27784c>] (dwc3_stop_active_transfer.constprop.4 [dwc3]) from [<bf27ab14>] (__dwc3_gadget_ep_disable+0x64/0x528 [dwc3])
[  141.861034] [<bf27ab14>] (__dwc3_gadget_ep_disable [dwc3]) from [<bf27c27c>] (dwc3_gadget_ep_disable+0x3c/0xc8 [dwc3])
[  141.872280] [<bf27c27c>] (dwc3_gadget_ep_disable [dwc3]) from [<bf23b428>] (usb_ep_disable+0x11c/0x18c [udc_core])
[  141.883160] [<bf23b428>] (usb_ep_disable [udc_core]) from [<bf342774>] (disable_ep+0x18/0x54 [usb_f_ss_lb])
[  141.893408] [<bf342774>] (disable_ep [usb_f_ss_lb]) from [<bf3437b0>] (disable_endpoints+0x18/0x50 [usb_f_ss_lb])
[  141.904168] [<bf3437b0>] (disable_endpoints [usb_f_ss_lb]) from [<bf343814>] (disable_source_sink+0x2c/0x34 [usb_f_ss_lb])
[  141.915771] [<bf343814>] (disable_source_sink [usb_f_ss_lb]) from [<bf329a9c>] (reset_config+0x48/0x7c [libcomposite])
[  141.927012] [<bf329a9c>] (reset_config [libcomposite]) from [<bf329afc>] (composite_disconnect+0x2c/0x54 [libcomposite])
[  141.938444] [<bf329afc>] (composite_disconnect [libcomposite]) from [<bf23d7dc>] (usb_gadget_udc_reset+0x10/0x34 [udc_core])
[  141.950237] [<bf23d7dc>] (usb_gadget_udc_reset [udc_core]) from [<bf276d70>] (dwc3_gadget_reset_interrupt+0x64/0x698 [dwc3])
[  141.962022] [<bf276d70>] (dwc3_gadget_reset_interrupt [dwc3]) from [<bf27952c>] (dwc3_thread_interrupt+0x618/0x1a3c [dwc3])
[  141.973723] [<bf27952c>] (dwc3_thread_interrupt [dwc3]) from [<c01a7ce8>] (irq_thread_fn+0x1c/0x54)
[  141.983215] [<c01a7ce8>] (irq_thread_fn) from [<c01a7fbc>] (irq_thread+0x120/0x1f0)
[  141.991247] [<c01a7fbc>] (irq_thread) from [<c015ba14>] (kthread+0xf8/0x138)
[  141.998641] [<c015ba14>] (kthread) from [<c01078f0>] (ret_from_fork+0x14/0x24)
[  142.006213] ---[ end trace b4ecfe9f175b9a9c ]---
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/gadget.c

@@ -3291,15 +3291,10 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
 
 int dwc3_gadget_suspend(struct dwc3 *dwc)
 {
-	int ret;
-
 	if (!dwc->gadget_driver)
 		return 0;
 
-	ret = dwc3_gadget_run_stop(dwc, false, false);
-	if (ret < 0)
-		return ret;
-
+	dwc3_gadget_run_stop(dwc, false, false);
 	dwc3_disconnect_gadget(dwc);
 	__dwc3_gadget_stop(dwc);