[media] v4l2: add const to argument of write-only s_register ioctl

This ioctl is defined as IOW, so pass the argument as const.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/i2c/mt9v011.c

@@ -421,7 +421,7 @@ static int mt9v011_g_register(struct v4l2_subdev *sd,
 }
 
 static int mt9v011_s_register(struct v4l2_subdev *sd,
-			      struct v4l2_dbg_register *reg)
+			      const struct v4l2_dbg_register *reg)
 {
 	struct i2c_client *client = v4l2_get_subdevdata(sd);