mlx4: add L3/L4 checksum offload
mlx4: add L3/L4 checksum offload

Mellanox ConnectX-3 adapters can handle L3 (IPv4) and L4 (TCP, UDP, TCP6,
UDP6) RX checksums validation and TX checksums generation, with and without
802.1Q (VLAN) headers.

Signed-off-by: Gilad Berman <6f4458b4cfab4168824a85dbf5d595be763db7c9@mellanox.com>
Signed-off-by: Olga Shern <94f6c1998eaef6808fd787423400815213eeb35d@mellanox.com>
Signed-off-by: Adrien Mazarguil <9d39ea493ca46c560334f650ac5d4b5ffbcb5cf0@6wind.com>

msune/dpdk,mixja/dpdk,venkynv/dpdk-mirror,mixja/dpdk,tsphillips/dpdk-fork,msune/dpdk,msune/dpdk,tsphillips/dpdk-fork,venkynv/dpdk-mirror,tsphillips/dpdk-fork,tsphillips/dpdk-fork,john-mcnamara-intel/dpdk,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,venkynv/dpdk-mirror,mixja/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,msune/dpdk,mixja/dpdk