[media] v4l2: make vidioc_s_jpegcomp const

Write-only ioctls should have a const argument in the ioctl op.
Do this conversion for vidioc_s_jpegcomp.
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>

drivers/media/usb/gspca/jeilinj.c

@@ -474,7 +474,7 @@ static int sd_init_controls(struct gspca_dev *gspca_dev)
 }
 
 static int sd_set_jcomp(struct gspca_dev *gspca_dev,
-			struct v4l2_jpegcompression *jcomp)
+			const struct v4l2_jpegcompression *jcomp)
 {
 	struct sd *sd = (struct sd *) gspca_dev;