ipv6: Pull IPv6 GSO registration out of the module

Sing GSO support is now separate, pull it out of the module
and make it its own init call.
Remove the cleanup functions as they are no longer called.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/udp_offload.c

@@ -115,8 +115,3 @@ int __init udp_offload_init(void)
 {
 	return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
 }
-
-void udp_offload_cleanup(void)
-{
-	inet6_del_offload(&udpv6_offload, IPPROTO_UDP);
-}