drm/virtio: batch resource creation

Move virtio_gpu_notify() to higher-level functions for
virtio_gpu_cmd_create_resource(), virtio_gpu_cmd_resource_create_3d()
and virtio_gpu_cmd_resource_attach_backing().

virtio_gpu_object_create() will batch commands and notify only once when
creating a resource.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20200214125535.26349-5-kraxel@redhat.com

drivers/gpu/drm/virtio/virtgpu_object.c

@@ -224,6 +224,7 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
 		return ret;
 	}
 
+	virtio_gpu_notify(vgdev);
 	*bo_ptr = bo;
 	return 0;