[media] media: vb2: reset queued_count value during queue reinitialization

queued_count variable was left untouched during the queue reinitialization
in __vb2_queue_cancel, what might lead to mismatch between the real number
of queued buffers and queued_count variable.

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
CC: Pawel Osciak <pawel@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/videobuf2-core.c

@@ -1189,6 +1189,7 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
 	 * has not already dequeued before initiating cancel.
 	 */
 	INIT_LIST_HEAD(&q->done_list);
+	atomic_set(&q->queued_count, 0);
 	wake_up_all(&q->done_wq);
 
 	/*