Input: imx_keypad - make of_device_id array const

Make of_device_id array const, because all OF functions handle it as const.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/imx_keypad.c

@@ -415,7 +415,7 @@ static int imx_keypad_open(struct input_dev *dev)
 }
 
 #ifdef CONFIG_OF
-static struct of_device_id imx_keypad_of_match[] = {
+static const struct of_device_id imx_keypad_of_match[] = {
 	{ .compatible = "fsl,imx21-kpp", },
 	{ /* sentinel */ }
 };