V4L/DVB (10133): v4l2-framework: use correct comment style.

Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Documentation/video4linux/v4l2-framework.txt

@@ -410,7 +410,7 @@ for you.
 
 	err = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
 	if (err) {
-		video_device_release(vdev); // or kfree(my_vdev);
+		video_device_release(vdev); /* or kfree(my_vdev); */
 		return err;
 	}