Revert "block: add __init to elv_register"

This reverts commit b5097e956a4d2919ee248d6481e4204c5568ed5c.

The original commit is buggy, we do use the registration functions
at runtime, for instance when loading IO schedulers through sysfs.

Reported-by: Damien Wyart <damien.wyart@gmail.com>

block/elevator.c

@@ -825,7 +825,7 @@ void elv_unregister_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL(elv_unregister_queue);
 
-int __init elv_register(struct elevator_type *e)
+int elv_register(struct elevator_type *e)
 {
 	char *def = "";
 

include/linux/elevator.h

@@ -143,7 +143,7 @@ extern void elv_drain_elevator(struct request_queue *);
  * io scheduler registration
  */
 extern void __init load_default_elevator_module(void);
-extern int __init elv_register(struct elevator_type *);
+extern int elv_register(struct elevator_type *);
 extern void elv_unregister(struct elevator_type *);
 
 /*