[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/platform/davinci/vpfe_capture.c b/drivers/media/platform/davinci/vpfe_capture.c
index f99198c..48052cb 100644
--- a/drivers/media/platform/davinci/vpfe_capture.c
+++ b/drivers/media/platform/davinci/vpfe_capture.c
@@ -1666,7 +1666,7 @@
 }
 
 static int vpfe_s_crop(struct file *file, void *priv,
-			     struct v4l2_crop *crop)
+			     const struct v4l2_crop *crop)
 {
 	struct vpfe_device *vpfe_dev = video_drvdata(file);
 	int ret = 0;