[media] v4l2: make vidioc_s_freq_hw_seek const

Write-only ioctls should have a const argument in the ioctl op.
Do this conversion for vidioc_s_freq_hw_seek.
Adding const for write-only ioctls was decided during the 2012 Media Workshop.

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-mr800.c b/drivers/media/radio/radio-mr800.c
index 3182b26..720bf0d 100644
--- a/drivers/media/radio/radio-mr800.c
+++ b/drivers/media/radio/radio-mr800.c
@@ -348,7 +348,7 @@
 }
 
 static int vidioc_s_hw_freq_seek(struct file *file, void *priv,
-		struct v4l2_hw_freq_seek *seek)
+		const struct v4l2_hw_freq_seek *seek)
 {
 	static u8 buf[8] = {
 		0x3d, 0x32, 0x0f, 0x08, 0x3d, 0x32, 0x0f, 0x08