[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/bt8xx/bttv-driver.c b/drivers/media/pci/bt8xx/bttv-driver.c
index 3156daf..7aea24b 100644
--- a/drivers/media/pci/bt8xx/bttv-driver.c
+++ b/drivers/media/pci/bt8xx/bttv-driver.c
@@ -1820,7 +1820,7 @@
 }
 
 static int bttv_s_tuner(struct file *file, void *priv,
-					struct v4l2_tuner *t)
+					const struct v4l2_tuner *t)
 {
 	struct bttv_fh *fh  = priv;
 	struct bttv *btv = fh->btv;
@@ -1830,8 +1830,11 @@
 
 	bttv_call_all(btv, tuner, s_tuner, t);
 
-	if (btv->audio_mode_gpio)
-		btv->audio_mode_gpio(btv, t, 1);
+	if (btv->audio_mode_gpio) {
+		struct v4l2_tuner copy = *t;
+
+		btv->audio_mode_gpio(btv, &copy, 1);
+	}
 	return 0;
 }
 
@@ -3279,7 +3282,7 @@
 }
 
 static int radio_s_tuner(struct file *file, void *priv,
-					struct v4l2_tuner *t)
+					const struct v4l2_tuner *t)
 {
 	struct bttv_fh *fh = priv;
 	struct bttv *btv = fh->btv;