usb: dwc3: Add error print messages

There is a possible race that arises when gadget events are processed
before the resume routine has disabled the USB2 PHY autosuspend. Some
of the gadget events issue endpoint commands which may time out since
the PHY is still autosuspended. Add error messages to help debug
these failurs.

Signed-off-by: Mayank Rana <mrana@codeaurora.org>