CHROMIUM: usb: dwc3: rockchip: Check for plug/unplug events on resume

CHROMIUM: usb: dwc3: rockchip: Check for plug/unplug events on resume

Check on resume if the cable state has changed to detect devices
(un)plugged during suspend.

TEST=build and boot on rk3399 board. No USB device plugged. Set
system enter suspend. Wait for device to suspend. Plug USB device.
Wakeup system; Verify USB device is enumerated.

Change-Id: Iadbefe6737fa3ddfe2da1a66473f876411a4412a
Signed-off-by: William Wu <wulf@rock-chips.com>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/395528
Reviewed-by: Guenter Roeck <groeck@chromium.org>