V4L/DVB: videobuf: add queue argument to videobuf_waiton()

videobuf_waiton() must unlock and relock ext_lock if it has to wait.
For that to happen it needs the videobuf_queue pointer.

Don't attempt to unlock/relock q->ext_lock unless it was locked in the
first place.

vb->state has to be protected by a spinlock to be safe.

This patch is based on code from Mauro Carvalho Chehab <mchehab@redhat.com>.

[mchehab@redhat.com: add extra argument to a few missing places]
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/mx1_camera.c b/drivers/media/video/mx1_camera.c
index 5c17f9e..e8a5ffc 100644
--- a/drivers/media/video/mx1_camera.c
+++ b/drivers/media/video/mx1_camera.c
@@ -161,7 +161,7 @@
 	 * This waits until this buffer is out of danger, i.e., until it is no
 	 * longer in STATE_QUEUED or STATE_ACTIVE
 	 */
-	videobuf_waiton(vb, 0, 0);
+	videobuf_waiton(vq, vb, 0, 0);
 	videobuf_dma_contig_free(vq, vb);
 
 	vb->state = VIDEOBUF_NEEDS_INIT;