[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>
diff --git a/drivers/media/i2c/mt9m032.c b/drivers/media/i2c/mt9m032.c
index f80c1d7e..2526b66 100644
--- a/drivers/media/i2c/mt9m032.c
+++ b/drivers/media/i2c/mt9m032.c
@@ -548,7 +548,7 @@
 }
 
 static int mt9m032_s_register(struct v4l2_subdev *sd,
-			      struct v4l2_dbg_register *reg)
+			      const struct v4l2_dbg_register *reg)
 {
 	struct mt9m032 *sensor = to_mt9m032(sd);
 	struct i2c_client *client = v4l2_get_subdevdata(&sensor->subdev);