[media] v4l2: make vidioc_s_crop const

Write-only ioctls should have a const argument in the ioctl op.
Do this conversion for vidioc_s_crop.
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/usb/pvrusb2/pvrusb2-v4l2.c b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
index 7a445b0..db249ca 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
@@ -760,7 +760,7 @@
 	return 0;
 }
 
-static int pvr2_s_crop(struct file *file, void *priv, struct v4l2_crop *crop)
+static int pvr2_s_crop(struct file *file, void *priv, const struct v4l2_crop *crop)
 {
 	struct pvr2_v4l2_fh *fh = file->private_data;
 	struct pvr2_hdw *hdw = fh->channel.mc_head->hdw;