block: add __init to elv_register

elv_register is only called by elevator init functions:

__init cfq_init
__init deadline_init
__init noop_init

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/elevator.c b/block/elevator.c
index 1e01b66..f35eddd 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -845,7 +845,7 @@
 }
 EXPORT_SYMBOL(elv_unregister_queue);
 
-int elv_register(struct elevator_type *e)
+int __init elv_register(struct elevator_type *e)
 {
 	char *def = "";
 
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index df63bd3..4ff262e 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -144,7 +144,7 @@
  * io scheduler registration
  */
 extern void __init load_default_elevator_module(void);
-extern int elv_register(struct elevator_type *);
+extern int __init elv_register(struct elevator_type *);
 extern void elv_unregister(struct elevator_type *);
 
 /*