drm/exynos: Remove event cancelling from postclose

The core takes care of this now. And since kfree(NULL) is ok we can
simplify the function even further now.

Note: There's another spin on this patch, but for different reasons,
in-flight already: http://www.spinics.net/lists/dri-devel/msg97922.html

Cc: Inki Dae <inki.dae@samsung.com>
Acked-by: NDaniel Stone <daniels@collabora.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Acked-by: NInki Dae <inki.dae@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-6-git-send-email-daniel.vetter@ffwll.ch

drivers/gpu/drm/exynos/exynos_drm_drv.c

@@ -340,20 +340,6 @@ static void exynos_drm_preclose(struct drm_device *dev,
 
 static void exynos_drm_postclose(struct drm_device *dev, struct drm_file *file)
 {
-	struct drm_pending_event *e, *et;
-	unsigned long flags;
-
-	if (!file->driver_priv)
-		return;
-
-	spin_lock_irqsave(&dev->event_lock, flags);
-	/* Release all events handled by page flip handler but not freed. */
-	list_for_each_entry_safe(e, et, &file->event_list, link) {
-		list_del(&e->link);
-		e->destroy(e);
-	}
-	spin_unlock_irqrestore(&dev->event_lock, flags);
-
 	kfree(file->driver_priv);
 	file->driver_priv = NULL;
 }