On shutdown, ehci_power_off() is called unconditionally to power off
each port, even if it was never called to power on the port.
For chipidea, this results in a call to ehci_ci_portpower() with a request
to power off ports even if the port was never powered on.
This results in the following warning from the regulator code.

WARNING: CPU: 0 PID: 182 at drivers/regulator/core.c:2596 _regulator_disable+0x1a8/0x210
unbalanced disables for usb_otg2_vbus
Modules linked in:
CPU: 0 PID: 182 Comm: init Not tainted 5.4.6 #1
Hardware name: Freescale i.MX7 Dual (Device Tree)
[<c0313658>] (unwind_backtrace) from [<c030d698>] (show_stack+0x10/0x14)
[<c030d698>] (show_stack) from [<c1133afc>] (dump_stack+0xe0/0x10c)
[<c1133afc>] (dump_stack) from [<c0349098>] (__warn+0xf4/0x10c)
[<c0349098>] (__warn) from [<c0349128>] (warn_slowpath_fmt+0x78/0xbc)
[<c0349128>] (warn_slowpath_fmt) from [<c09f36ac>] (_regulator_disable+0x1a8/0x210)
[<c09f36ac>] (_regulator_disable) from [<c09f374c>] (regulator_disable+0x38/0xe8)
[<c09f374c>] (regulator_disable) from [<c0df7bac>] (ehci_ci_portpower+0x38/0xdc)
[<c0df7bac>] (ehci_ci_portpower) from [<c0db4fa4>] (ehci_port_power+0x50/0xa4)
[<c0db4fa4>] (ehci_port_power) from [<c0db5420>] (ehci_silence_controller+0x5c/0xc4)
[<c0db5420>] (ehci_silence_controller) from [<c0db7644>] (ehci_stop+0x3c/0xcc)
[<c0db7644>] (ehci_stop) from [<c0d5bdc4>] (usb_remove_hcd+0xe0/0x19c)
[<c0d5bdc4>] (usb_remove_hcd) from [<c0df7638>] (host_stop+0x38/0xa8)
[<c0df7638>] (host_stop) from [<c0df2f34>] (ci_hdrc_remove+0x44/0xe4)
...

Keeping track of the power enable state avoids the warning and traceback.

Fixes: c8679a2f ("usb: chipidea: host: add portpower override")
Cc: Michael Grzeschik <m.grzeschik@pengutronix.de>
Cc: Peter Chen <peter.chen@freescale.com>
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Peter Chen <peter.chen@nxp.com>
Link: https://lore.kernel.org/r/20191226155754.25451-1-linux@roeck-us.netSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>