workqueue: Calling destroy_work_on_stack() to pair with INIT_WORK_ONSTACK()

In case CONFIG_DEBUG_OBJECTS_WORK is defined, it is needed to
call destroy_work_on_stack() which frees the debug object to pair
with INIT_WORK_ONSTACK().
Signed-off-by: NLiu, Chuansheng <chuansheng.liu@intel.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

kernel/workqueue.c

@@ -4776,6 +4776,7 @@ static int workqueue_cpu_down_callback(struct notifier_block *nfb,
 
 		/* wait for per-cpu unbinding to finish */
 		flush_work(&unbind_work);
+		destroy_work_on_stack(&unbind_work);
 		break;
 	}
 	return NOTIFY_OK;
@@ -4822,6 +4823,7 @@ long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
 	 */
 	__flush_work(&wfc.work);
 
+	destroy_work_on_stack(&wfc.work);
 	return wfc.ret;
 }
 EXPORT_SYMBOL_GPL(work_on_cpu);