media: cx88: Get rid of spurious call to cx8800_start_vbi_dma()

This was left over from the conversion to VB2, where the call was
getting invoked both in buffer_queue and start_streaming, which
was intermittently causing invalid opcodes on the VBI RISC queue.

This change effectively mirrors the exact same change Hans Verkuil
made in cx88-video.c in commit 389208e1 ("[media] cx88:
remove leftover start_video_dma() call").

Thanks to Daniel Glöckner for spotting the actual bug after I spent
several days trying to chase down the issue.

Fixes: 389208e1 ("[media] cx88: remove leftover start_video_dma() call")
Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Thanks-to: Daniel Glöckner <daniel-gl@gmx.net>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

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

@@ -178,7 +178,6 @@ static void buffer_queue(struct vb2_buffer *vb)
 
 	if (list_empty(&q->active)) {
 		list_add_tail(&buf->list, &q->active);
-		cx8800_start_vbi_dma(dev, q, buf);
 		dprintk(2, "[%p/%d] vbi_queue - first active\n",
 			buf, buf->vb.vb2_buf.index);