[media] media: cx88: use vb2_start_streaming_called() helper

this patch adds support for using vb2_start_streaming_called()
for cx88-blackbird driver.
Signed-off-by: NLad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/pci/cx88/cx88-blackbird.c

@@ -881,7 +881,7 @@ static int vidioc_s_frequency (struct file *file, void *priv,
 		return -EINVAL;
 	if (unlikely(f->tuner != 0))
 		return -EINVAL;
-	streaming = dev->vb2_mpegq.start_streaming_called;
+	streaming = vb2_start_streaming_called(&dev->vb2_mpegq);
 	if (streaming)
 		blackbird_stop_codec(dev);