drm/arc: Implement nonblocking commit correctly

Committing with block it is not.

Thanks to the fixed up vblank event handling we can just use the
helper support for nonblocking commits now.

Cc: Carlos Palminha <palminha@synopsys.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1465388359-8070-11-git-send-email-daniel.vetter@ffwll.ch

drivers/gpu/drm/arc/arcpgu_drv.c

@@ -32,17 +32,11 @@ static void arcpgu_fb_output_poll_changed(struct drm_device *dev)
 		drm_fbdev_cma_hotplug_event(arcpgu->fbdev);
 }
 
-static int arcpgu_atomic_commit(struct drm_device *dev,
-				    struct drm_atomic_state *state, bool async)
-{
-	return drm_atomic_helper_commit(dev, state, false);
-}
-
 static struct drm_mode_config_funcs arcpgu_drm_modecfg_funcs = {
 	.fb_create  = drm_fb_cma_create,
 	.output_poll_changed = arcpgu_fb_output_poll_changed,
 	.atomic_check = drm_atomic_helper_check,
-	.atomic_commit = arcpgu_atomic_commit,
+	.atomic_commit = drm_atomic_helper_commit,
 };
 
 static void arcpgu_setup_mode_config(struct drm_device *drm)