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

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

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/radio/radio-ma901.c b/drivers/media/radio/radio-ma901.c
index c61f590..7f85c6f 100644
--- a/drivers/media/radio/radio-ma901.c
+++ b/drivers/media/radio/radio-ma901.c
@@ -257,7 +257,7 @@
 
 /* vidioc_s_frequency - set tuner radio frequency */
 static int vidioc_s_frequency(struct file *file, void *priv,
-				struct v4l2_frequency *f)
+				const struct v4l2_frequency *f)
 {
 	struct ma901radio_device *radio = video_drvdata(file);