drm/kirin: Drop drm_vblank_cleanup

Again we probably want a drm_atomic_helper_shutdown somewhere, but
that's a bit more analysis.

Cc: Xinliang Liu <z.liuxinliang@hisilicon.com>
Cc: Rongrong Zou <zourongrong@gmail.com>
Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com>
Cc: Chen Feng <puck.chen@hisilicon.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170621082850.13224-4-daniel.vetter@ffwll.ch

drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c

@@ -41,7 +41,6 @@ static int kirin_drm_kms_cleanup(struct drm_device *dev)
 	}
 #endif
 	drm_kms_helper_poll_fini(dev);
-	drm_vblank_cleanup(dev);
 	dc_ops->cleanup(to_platform_device(dev->dev));
 	drm_mode_config_cleanup(dev);
 	devm_kfree(dev->dev, priv);