drm/fence: release fence reference when canceling event

If the event gets canceled we also need to put away the fence
reference it holds.
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1476975005-30441-3-git-send-email-gustavo@padovan.org

drivers/gpu/drm/drm_fops.c

@@ -663,6 +663,10 @@ void drm_event_cancel_free(struct drm_device *dev,
 		list_del(&p->pending_link);
 	}
 	spin_unlock_irqrestore(&dev->event_lock, flags);
+
+	if (p->fence)
+		fence_put(p->fence);
+
 	kfree(p);
 }
 EXPORT_SYMBOL(drm_event_cancel_free);