[media] v4l2: make vidioc_s_fbuf const

Write-only ioctls should have a const argument in the ioctl op.
Do this conversion for vidioc_s_fbuf.
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/pci/zoran/zoran_driver.c

@@ -1978,7 +1978,7 @@ static int zoran_g_fbuf(struct file *file, void *__fh,
 }
 
 static int zoran_s_fbuf(struct file *file, void *__fh,
-		struct v4l2_framebuffer *fb)
+		const struct v4l2_framebuffer *fb)
 {
 	struct zoran_fh *fh = __fh;
 	struct zoran *zr = fh->zr;