sysctl: Remove dead register_sysctl_root

The function no longer does anything.  The is only a single caller of
register_sysctl_root when semantically there should be two.  Remove
this function so that if someone decides this functionality is needed
again it will be obvious all of the callers of setup_sysctl_set need
to be audited and modified appropriately.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

fs/proc/proc_sysctl.c

@@ -408,10 +408,6 @@ static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentr
 	*pentry = entry;
 }
 
-void register_sysctl_root(struct ctl_table_root *root)
-{
-}
-
 /*
  * sysctl_perm does NOT grant the superuser all rights automatically, because
  * some sysctl variables are readonly even to root.

include/linux/sysctl.h

@@ -180,7 +180,6 @@ extern void setup_sysctl_set(struct ctl_table_set *p,
 	int (*is_seen)(struct ctl_table_set *));
 extern void retire_sysctl_set(struct ctl_table_set *set);
 
-void register_sysctl_root(struct ctl_table_root *root);
 struct ctl_table_header *__register_sysctl_table(
 	struct ctl_table_set *set,
 	const char *path, struct ctl_table *table);

net/sysctl_net.c

@@ -106,7 +106,6 @@ __init int net_sysctl_init(void)
 	ret = register_pernet_subsys(&sysctl_pernet_ops);
 	if (ret)
 		goto out1;
-	register_sysctl_root(&net_sysctl_root);
 out:
 	return ret;
 out1: