usb: gadget: udc: atmel: GPIO inversion is handled by gpiod

When converting to GPIO descriptors, gpiod_get_value automatically
handles the line inversion flags from the device tree.

Do not invert the line twice.

Fixes: 3df03408

 ("usb: gadget: udc: atmel: convert to use GPIO descriptors")
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>