rtnetlink: Remove passing of attributes into rtnl_doit functions

With decnet converted, we can finally get rid of rta_buf and its
computations around it. It also gets rid of the minimal header
length verification since all message handlers do that explicitly
anyway.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index 5a15fab..7026648 100644
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -4,7 +4,7 @@
 #include <linux/rtnetlink.h>
 #include <net/netlink.h>
 
-typedef int (*rtnl_doit_func)(struct sk_buff *, struct nlmsghdr *, void *);
+typedef int (*rtnl_doit_func)(struct sk_buff *, struct nlmsghdr *);
 typedef int (*rtnl_dumpit_func)(struct sk_buff *, struct netlink_callback *);
 typedef u16 (*rtnl_calcit_func)(struct sk_buff *, struct nlmsghdr *);