usb: gadget: pch_udc: switch over to usb_gadget_map/unmap_request()

We have generic implementations for a reason, let's use them.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210325135508.70350-1-andriy.shevchenko@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>