V4L/DVB: videobuf: add ext_lock argument to the queue init functions

Add an ext_lock argument to the videobuf init functions. This allows
drivers to pass the vdev->lock pointer (or any other externally held lock)
to videobuf. For now all drivers just pass NULL.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/saa7134/saa7134-empress.c b/drivers/media/video/saa7134/saa7134-empress.c
index e763f9f..1467a30 100644
--- a/drivers/media/video/saa7134/saa7134-empress.c
+++ b/drivers/media/video/saa7134/saa7134-empress.c
@@ -542,7 +542,7 @@
 			    V4L2_BUF_TYPE_VIDEO_CAPTURE,
 			    V4L2_FIELD_ALTERNATE,
 			    sizeof(struct saa7134_buf),
-			    dev);
+			    dev, NULL);
 
 	empress_signal_update(&dev->empress_workqueue);
 	return 0;