staging/android: do not let userspace trigger WARN_ON

Closing the timeline without waiting all fences to signal is not
a critical failure, it is just bad usage from userspace so avoid
calling WARN_ON in this case.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/sw_sync.c

@@ -176,7 +176,7 @@ static void timeline_fence_release(struct fence *fence)
 
 	spin_lock_irqsave(fence->lock, flags);
 	list_del(&pt->child_list);
-	if (WARN_ON_ONCE(!list_empty(&pt->active_list)))
+	if (!list_empty(&pt->active_list))
 		list_del(&pt->active_list);
 	spin_unlock_irqrestore(fence->lock, flags);