drm/virtio: Add missing virtqueue reset

As per the VirtIO spec, the virtqueues must be reset during cleanup
(see "3.3.1 Driver Requirements: Device Cleanup").
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20190102175507.4653-2-ezequiel@collabora.com

drivers/gpu/drm/virtio/virtgpu_kms.c

@@ -239,6 +239,7 @@ void virtio_gpu_driver_unload(struct drm_device *dev)
 	flush_work(&vgdev->ctrlq.dequeue_work);
 	flush_work(&vgdev->cursorq.dequeue_work);
 	flush_work(&vgdev->config_changed_work);
+	vgdev->vdev->config->reset(vgdev->vdev);
 	vgdev->vdev->config->del_vqs(vgdev->vdev);
 
 	virtio_gpu_modeset_fini(vgdev);