drm: virtio-gpu: set atomic flag

Advertise atomic mode setting capability to user space.
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/virtio/virtgpu_drv.c

@@ -118,7 +118,7 @@ static const struct file_operations virtio_gpu_driver_fops = {
 
 
 static struct drm_driver driver = {
-	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME | DRIVER_RENDER,
+	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME | DRIVER_RENDER | DRIVER_ATOMIC,
 	.set_busid = drm_virtio_set_busid,
 	.load = virtio_gpu_driver_load,
 	.unload = virtio_gpu_driver_unload,