usb: dwc3: xilinx: Remove unused of_gpio,h

of_gpio.h provides a single function, which is not used in this driver.
Remove unused header.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20230215165239.83806-1-andriy.shevchenko@linux.intel.com


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