Fix broken backport for IPv6 tunnels

Fix broken backport for IPv6 tunnels in 2.6.32-longterm kernels.

upstream commit d5aa407f ("tunnels: fix
netns vs proto registration ordering") , which was included in
2.6.32.44-longterm, was not backported correctly, and results in a NULL
pointer dereference in ip6_tunnel.c for longterm kernels >=2.6.32.44

Use [un]register_pernet_gen_device() instead of
[un]register_pernet_device() to fix it.
Signed-off-by: Stratos Psomadakis <psomas@gentoo.org>
Cc: Wolfgang Walter <wolfgang.walter@stwm.de>
Cc: Tim Gardner <tim.gardner@canonical.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

net/ipv6/ip6_tunnel.c

@@ -1466,7 +1466,7 @@ static int __init ip6_tunnel_init(void)
 {
 	int  err;
 
-	err = register_pernet_device(&ip6_tnl_net_ops);
+	err = register_pernet_gen_device(&ip6_tnl_net_id, &ip6_tnl_net_ops);
 	if (err < 0)
 		goto out_pernet;
 
@@ -1487,7 +1487,7 @@ static int __init ip6_tunnel_init(void)
 out_ip6ip6:
 	xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET);
 out_ip4ip6:
-	unregister_pernet_device(&ip6_tnl_net_ops);
+	unregister_pernet_gen_device(ip6_tnl_net_id, &ip6_tnl_net_ops);
 out_pernet:
 	return err;
 }