This patch reuses the code in xfrm6_input.c for receiving xfrm6_tunnel
packets.  This removes duplicate code as well as fixing the bugs unique
to xfrm6_tunnel_input.  For example, it didn't move the MAC header down.
Nor did it do anything with ECN.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@redhat.com>