workqueue: Add destroy_work_on_stack() in workqueue_softirq_dead()

This commit add missed destroy_work_on_stack() operations for
dead_work.work.

Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/workqueue.c

@@ -3661,6 +3661,7 @@ void workqueue_softirq_dead(unsigned int cpu)
 			queue_work(system_bh_wq, &dead_work.work);
 
 		wait_for_completion(&dead_work.done);
+		destroy_work_on_stack(&dead_work.work);
 	}
 }