ipv4, ipv6: kill ip_mc_{join, leave}_group and ipv6_sock_mc_{join, drop}

in favor of their inner __ ones, which doesn't grab rtnl.

As these functions need to operate on a locked socket, we can't be
grabbing rtnl by then. It's too late and doing so causes reversed
locking.

So this patch:
- move rtnl handling to callers instead while already fixing some
  reversed locking situations, like on vxlan and ipvs code.
- renames __ ones to not have the __ mark:
  __ip_mc_{join,leave}_group -> ip_mc_{join,leave}_group
  __ipv6_sock_mc_{join,drop} -> ipv6_sock_mc_{join,drop}

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 88d2cf0..158378e 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2473,9 +2473,9 @@
 
 	lock_sock(sk);
 	if (join)
-		ret = __ipv6_sock_mc_join(sk, ifindex, addr);
+		ret = ipv6_sock_mc_join(sk, ifindex, addr);
 	else
-		ret = __ipv6_sock_mc_drop(sk, ifindex, addr);
+		ret = ipv6_sock_mc_drop(sk, ifindex, addr);
 	release_sock(sk);
 
 	return ret;