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/net/decnet/dn_fib.c b/net/decnet/dn_fib.c
index 42a8048..f093059 100644
--- a/net/decnet/dn_fib.c
+++ b/net/decnet/dn_fib.c
@@ -511,7 +511,7 @@
 	return table;
 }
 
-static int dn_fib_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
+static int dn_fib_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct net *net = sock_net(skb->sk);
 	struct dn_fib_table *tb;
@@ -536,7 +536,7 @@
 	return tb->delete(tb, r, attrs, nlh, &NETLINK_CB(skb));
 }
 
-static int dn_fib_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
+static int dn_fib_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct net *net = sock_net(skb->sk);
 	struct dn_fib_table *tb;