blk-mq: free hctx->ctx_map when init failed

Avoid memory leak in the failure path.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

block/blk-mq.c

@@ -1289,6 +1289,7 @@ static int blk_mq_init_hw_queues(struct request_queue *q,
 
 		blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
 		kfree(hctx->ctxs);
+		kfree(hctx->ctx_map);
 	}
 
 	return 1;