[media] uvc gadget: set device_caps in querycap

The V4L2 core will warn if this is not done. Unfortunately this driver
wasn't updated.

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

drivers/usb/gadget/function/uvc_v4l2.c

···
 	strlcpy(cap->bus_info, dev_name(&cdev->gadget->dev),
 		sizeof(cap->bus_info));
 
-	cap->capabilities = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
+	cap->device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
+	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
 
 	return 0;
 }