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

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

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Alexey Klimov <klimov.linux@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/i2c/tda9840.c b/drivers/media/i2c/tda9840.c
index 3d7ddd9..01441e3 100644
--- a/drivers/media/i2c/tda9840.c
+++ b/drivers/media/i2c/tda9840.c
@@ -87,7 +87,7 @@
 	return byte & 0x60;
 }
 
-static int tda9840_s_tuner(struct v4l2_subdev *sd, struct v4l2_tuner *t)
+static int tda9840_s_tuner(struct v4l2_subdev *sd, const struct v4l2_tuner *t)
 {
 	int stat = tda9840_status(sd);
 	int byte;