drm/hibmc: Drop drm_vblank_cleanup

So this seems to be the first driver that does it the right way round,
so fix it up by calling drm_atomic_helper_shutdown instead. We need to
do that before the last kms user is gone (fbdev emulation), but before
we start shutting down hw stuff like interrupts.

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: NSean Paul <seanpaul@chromium.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170621082850.13224-3-daniel.vetter@ffwll.ch

drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c

@@ -276,11 +276,12 @@ static int hibmc_unload(struct drm_device *dev)
 
 	hibmc_fbdev_fini(priv);
 
+	drm_atomic_helper_shutdown(dev);
+
 	if (dev->irq_enabled)
 		drm_irq_uninstall(dev);
 	if (priv->msi_enabled)
 		pci_disable_msi(dev->pdev);
-	drm_vblank_cleanup(dev);
 
 	hibmc_kms_fini(priv);
 	hibmc_mm_fini(priv);