[media] vim2m: add create_bufs and prepare_buf support

Add support for the missing VIDIOC_CREATE_BUFS and VIDIOC_PREPARE_BUF
ioctls.

Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/platform/vim2m.c

···
 	.vidioc_querybuf	= v4l2_m2m_ioctl_querybuf,
 	.vidioc_qbuf		= v4l2_m2m_ioctl_qbuf,
 	.vidioc_dqbuf		= v4l2_m2m_ioctl_dqbuf,
+	.vidioc_prepare_buf	= v4l2_m2m_ioctl_prepare_buf,
+	.vidioc_create_bufs	= v4l2_m2m_ioctl_create_bufs,
 	.vidioc_expbuf		= v4l2_m2m_ioctl_expbuf,
 
 	.vidioc_streamon	= v4l2_m2m_ioctl_streamon,
···
 	q_data = get_q_data(ctx, vq->type);
 
 	size = q_data->width * q_data->height * q_data->fmt->depth >> 3;
+
+	if (fmt) {
+		if (fmt->fmt.pix.sizeimage < size)
+			return -EINVAL;
+		size = fmt->fmt.pix.sizeimage;
+	}
 
 	while (size * count > MEM2MEM_VID_MEM_LIMIT)
 		(count)--;