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/ipv4/devinet.c b/net/ipv4/devinet.c
index af57bba..20a9f92 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -536,7 +536,7 @@
 	return NULL;
 }
 
-static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
+static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct net *net = sock_net(skb->sk);
 	struct nlattr *tb[IFA_MAX+1];
@@ -775,7 +775,7 @@
 	return NULL;
 }
 
-static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
+static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
 	struct net *net = sock_net(skb->sk);
 	struct in_ifaddr *ifa;
@@ -1730,8 +1730,7 @@
 };
 
 static int inet_netconf_get_devconf(struct sk_buff *in_skb,
-				    struct nlmsghdr *nlh,
-				    void *arg)
+				    struct nlmsghdr *nlh)
 {
 	struct net *net = sock_net(in_skb->sk);
 	struct nlattr *tb[NETCONFA_MAX+1];