[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>
diff --git a/drivers/media/usb/gspca/gspca.c b/drivers/media/usb/gspca/gspca.c
index 2abbf52..a2b9341 100644
--- a/drivers/media/usb/gspca/gspca.c
+++ b/drivers/media/usb/gspca/gspca.c
@@ -1686,7 +1686,7 @@
 }
 
 static int vidioc_s_jpegcomp(struct file *file, void *priv,
-			struct v4l2_jpegcompression *jpegcomp)
+			const struct v4l2_jpegcompression *jpegcomp)
 {
 	struct gspca_dev *gspca_dev = video_drvdata(file);