netfilter: conntrack: Change to deferable work queue

Delayed workqueue causes wakeups to idle CPUs. This was
causing a power impact for devices. Use deferable work
queue instead so that gc_worker runs when CPU is active only.
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_conntrack_core.c

@@ -1081,7 +1081,7 @@ static void gc_worker(struct work_struct *work)
 
 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
 {
-	INIT_DELAYED_WORK(&gc_work->dwork, gc_worker);
+	INIT_DEFERRABLE_WORK(&gc_work->dwork, gc_worker);
 	gc_work->next_gc_run = HZ;
 	gc_work->exiting = false;
 }