media: usb: rainshadow-cec: constify serio_device_id

serio_device_id are not supposed to change at runtime. All functions
working with serio_device_id provided by <linux/serio.h> work with
const serio_device_id. So mark the non-const structs as const.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/usb/rainshadow-cec/rainshadow-cec.c

@@ -358,7 +358,7 @@ static int rain_connect(struct serio *serio, struct serio_driver *drv)
 	return err;
 }
 
-static struct serio_device_id rain_serio_ids[] = {
+static const struct serio_device_id rain_serio_ids[] = {
 	{
 		.type	= SERIO_RS232,
 		.proto	= SERIO_RAINSHADOW_CEC,