media: usb: cx231xx: Stop direct calls to queue num_buffers field

Use vb2_get_num_buffers() to avoid using queue num_buffers field directly.
This allows us to change how the number of buffers is computed in the
future.

Signed-off-by: Benjamin Gaignard <[e-mail]>
Reviewed-by: Andrzej Pietrasiewicz <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/usb/cx231xx/cx231xx-417.c

···
 {
 	struct cx231xx *dev = vb2_get_drv_priv(vq);
 	unsigned int size = mpeglinesize * mpeglines;
+	unsigned int q_num_bufs = vb2_get_num_buffers(vq);
 
 	dev->ts1.ts_packet_size  = mpeglinesize;
 	dev->ts1.ts_packet_count = mpeglines;
 
-	if (vq->num_buffers + *nbuffers < CX231XX_MIN_BUF)
-		*nbuffers = CX231XX_MIN_BUF - vq->num_buffers;
+	if (q_num_bufs + *nbuffers < CX231XX_MIN_BUF)
+		*nbuffers = CX231XX_MIN_BUF - q_num_bufs;
 
 	if (*nplanes)
 		return sizes[0] < size ? -EINVAL : 0;

drivers/media/usb/cx231xx/cx231xx-video.c

···
 		       unsigned int sizes[], struct device *alloc_devs[])
 {
 	struct cx231xx *dev = vb2_get_drv_priv(vq);
+	unsigned int q_num_bufs = vb2_get_num_buffers(vq);
 
 	dev->size = (dev->width * dev->height * dev->format->depth + 7) >> 3;
 
-	if (vq->num_buffers + *nbuffers < CX231XX_MIN_BUF)
-		*nbuffers = CX231XX_MIN_BUF - vq->num_buffers;
+	if (q_num_bufs + *nbuffers < CX231XX_MIN_BUF)
+		*nbuffers = CX231XX_MIN_BUF - q_num_bufs;
 
 	if (*nplanes)
 		return sizes[0] < dev->size ? -EINVAL : 0;