[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/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index 73ae24a..21f6245 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -195,7 +195,7 @@
 	int (*vidioc_g_jpegcomp)       (struct file *file, void *fh,
 					struct v4l2_jpegcompression *a);
 	int (*vidioc_s_jpegcomp)       (struct file *file, void *fh,
-					struct v4l2_jpegcompression *a);
+					const struct v4l2_jpegcompression *a);
 	int (*vidioc_g_enc_index)      (struct file *file, void *fh,
 					struct v4l2_enc_idx *a);
 	int (*vidioc_encoder_cmd)      (struct file *file, void *fh,