netlink: cleanup rntl_af_register

The function __rtnl_af_register is never called outside this
code, and the return value is always 0.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index bb13a18..8fb4207 100644
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -115,10 +115,9 @@
 					       const struct nlattr *attr);
 };
 
-int __rtnl_af_register(struct rtnl_af_ops *ops);
 void __rtnl_af_unregister(struct rtnl_af_ops *ops);
 
-int rtnl_af_register(struct rtnl_af_ops *ops);
+void rtnl_af_register(struct rtnl_af_ops *ops);
 void rtnl_af_unregister(struct rtnl_af_ops *ops);
 
 struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]);