The enic TSO implementation requires that the length of the Eth/IP/TCP
headers be passed to the NIC. Other than that, it's just a matter of
setting the mss and offload mode on a per packet basis.
In TSO mode, IP and TCP checksums are offloaded even if not requested
with mb->ol_flags.
Signed-off-by: John Daley <johndale@cisco.com>