block: blk-mq: don't export blk_mq_free_queue()

blk_mq_free_queue() is called from release handler of
queue kobject, so it needn't be called from drivers.

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 9777952..8095c4a 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -11,6 +11,7 @@
 
 #include "blk.h"
 #include "blk-cgroup.h"
+#include "blk-mq.h"
 
 struct queue_sysfs_entry {
 	struct attribute attr;