usb: gadget: gr_udc: Make of_device_id array const

Make of_device_id array const, because all OF functions handle
it as const.

Acked-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
1 file changed