blk-mq: turn hctx->run_work into a regular work struct

We don't need the larger delayed work struct, since we always run it
immediately.

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-core.c b/block/blk-core.c
index 2d08597..34ff808 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -288,7 +288,7 @@
 		int i;
 
 		queue_for_each_hw_ctx(q, hctx, i) {
-			cancel_delayed_work_sync(&hctx->run_work);
+			cancel_work_sync(&hctx->run_work);
 			cancel_delayed_work_sync(&hctx->delay_work);
 		}
 	} else {