drm/vc4: Add missing render node support

There shouldn't be any other driver support necessary, since none of
the driver-specific ioctls ever required auth, and none of them deal
with modesetting.
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/vc4/vc4_drv.c

@@ -81,6 +81,7 @@ static struct drm_driver vc4_drm_driver = {
 			    DRIVER_ATOMIC |
 			    DRIVER_GEM |
 			    DRIVER_HAVE_IRQ |
+			    DRIVER_RENDER |
 			    DRIVER_PRIME),
 	.lastclose = vc4_lastclose,
 	.irq_handler = vc4_irq,