usb: gadget: uvc: Add support for DMABUF importing

Activate the videobuf2 DMABUF support. As vb2-vmalloc supports the
importer role only, exporting buffers isn't supported yet. When the
exporter role will be implemented in vb2-vmalloc the UVC gadget driver
will automatically gain support for it.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/uvc_queue.c

@@ -132,7 +132,7 @@ static int uvc_queue_init(struct uvc_video_queue *queue,
 	int ret;
 
 	queue->queue.type = type;
-	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
+	queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
 	queue->queue.drv_priv = queue;
 	queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
 	queue->queue.ops = &uvc_queue_qops;