usb: gadget: udc: atmel: Check fifo configuration values against device tree

Check fifo configuration values against device tree values for endpoint fifo
in auto configuration mode (fifo_mode=0).

Signed-off-by: Cristian Birsan <cristian.birsan@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>