V4L/DVB (8414): videodev/cx18: fix get_index bug and error-handling lock-ups

Fix a bug in get_index that was introduced earlier.
Also fix two error handling lock-ups in videodev and cx18 that
where found thanks to that bug.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/cx18/cx18-streams.c b/drivers/media/video/cx18/cx18-streams.c
index f3d2050..1728b1d 100644
--- a/drivers/media/video/cx18/cx18-streams.c
+++ b/drivers/media/video/cx18/cx18-streams.c
@@ -311,8 +311,10 @@
 
 	/* Teardown all streams */
 	for (type = 0; type < CX18_MAX_STREAMS; type++) {
-		if (cx->streams[type].dvb.enabled)
+		if (cx->streams[type].dvb.enabled) {
 			cx18_dvb_unregister(&cx->streams[type]);
+			cx->streams[type].dvb.enabled = false;
+		}
 
 		vdev = cx->streams[type].v4l2dev;