[IPv6] route: Simplify ip6_ins_rt()

Provide a simple ip6_ins_rt() for the majority of users and
an alternative for the exception via netlink. Avoids code
obfuscation.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index f6881d7..abbc35a 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -335,7 +335,7 @@
 	write_unlock_bh(&idev->lock);
 
 	dst_hold(&rt->u.dst);
-	if (ip6_ins_rt(rt, NULL, NULL, NULL))
+	if (ip6_ins_rt(rt))
 		dst_release(&rt->u.dst);
 
 	addrconf_join_solict(dev, &aca->aca_addr);