lwt: Add cfg argument to build_state

Add cfg and family arguments to lwt build state functions. cfg is a void
pointer and will either be a pointer to a fib_config or fib6_config
structure. The family parameter indicates which one (either AF_INET
or AF_INET6).

LWT encpasulation implementation may use the fib configuration to build
the LWT state.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
index 3da5ca3..21e70bc 100644
--- a/net/mpls/mpls_iptunnel.c
+++ b/net/mpls/mpls_iptunnel.c
@@ -123,6 +123,7 @@
 }
 
 static int mpls_build_state(struct net_device *dev, struct nlattr *nla,
+			    unsigned int family, const void *cfg,
 			    struct lwtunnel_state **ts)
 {
 	struct mpls_iptunnel_encap *tun_encap_info;