[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/pci/cx25821/cx25821-video.c b/drivers/media/pci/cx25821/cx25821-video.c
index 1219d60..75281c1 100644
--- a/drivers/media/pci/cx25821/cx25821-video.c
+++ b/drivers/media/pci/cx25821/cx25821-video.c
@@ -1397,7 +1397,7 @@
 	return 0;
 }
 
-int cx25821_vidioc_s_tuner(struct file *file, void *priv, struct v4l2_tuner *t)
+int cx25821_vidioc_s_tuner(struct file *file, void *priv, const struct v4l2_tuner *t)
 {
 	struct cx25821_dev *dev = ((struct cx25821_fh *)priv)->dev;
 	struct cx25821_fh *fh = priv;
diff --git a/drivers/media/pci/cx25821/cx25821-video.h b/drivers/media/pci/cx25821/cx25821-video.h
index 969340c..f0e70ff 100644
--- a/drivers/media/pci/cx25821/cx25821-video.h
+++ b/drivers/media/pci/cx25821/cx25821-video.h
@@ -159,7 +159,7 @@
 extern int cx25821_vidioc_g_tuner(struct file *file, void *priv,
 				  struct v4l2_tuner *t);
 extern int cx25821_vidioc_s_tuner(struct file *file, void *priv,
-				  struct v4l2_tuner *t);
+				  const struct v4l2_tuner *t);
 
 extern int cx25821_is_valid_width(u32 width, v4l2_std_id tvnorm);
 extern int cx25821_is_valid_height(u32 height, v4l2_std_id tvnorm);