block: kill blk_start_queueing()

blk_start_queueing() is identical to __blk_run_queue() except that it
doesn't check for recursion.  None of the current users depends on
blk_start_queueing() running request_fn directly.  Replace usages of
blk_start_queueing() with [__]blk_run_queue() and kill it.

[ Impact: removal of mostly duplicate interface function ]

Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/block/as-iosched.c b/block/as-iosched.c
index c48fa67..45bd070 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -1312,12 +1312,8 @@
 static void as_work_handler(struct work_struct *work)
 {
 	struct as_data *ad = container_of(work, struct as_data, antic_work);
-	struct request_queue *q = ad->q;
-	unsigned long flags;
 
-	spin_lock_irqsave(q->queue_lock, flags);
-	blk_start_queueing(q);
-	spin_unlock_irqrestore(q->queue_lock, flags);
+	blk_run_queue(ad->q);
 }
 
 static int as_may_queue(struct request_queue *q, int rw)