Adding IPv6 for the TSO helper API is trivial:
* Don't play with the id (which doesn't exist in IPv6)
* Correctly update the payload_len (don't include the
  length of the IP header itself)
Signed-off-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>