workqueue: make deferrable delayed_work initializer names consistent

Initalizers for deferrable delayed_work are confused.

* __DEFERRED_WORK_INITIALIZER()
* DECLARE_DEFERRED_WORK()
* INIT_DELAYED_WORK_DEFERRABLE()

Rename them to

* __DEFERRABLE_WORK_INITIALIZER()
* DECLARE_DEFERRABLE_WORK()
* INIT_DEFERRABLE_WORK()

This patch doesn't cause any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/mm/slab.c b/mm/slab.c
index f8b0d53..35b5cb0 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -900,7 +900,7 @@
 	 */
 	if (keventd_up() && reap_work->work.func == NULL) {
 		init_reap_node(cpu);
-		INIT_DELAYED_WORK_DEFERRABLE(reap_work, cache_reap);
+		INIT_DEFERRABLE_WORK(reap_work, cache_reap);
 		schedule_delayed_work_on(cpu, reap_work,
 					__round_jiffies_relative(HZ, cpu));
 	}