net: thunderx: HW TSO support for pass-2 hardware

This adds support for offloading TCP segmentation to HW in pass-2
revision of hardware. Both driver level SW TSO for pass1.x chips
and HW TSO for pass-2 chip will co-exist. Modified SQ descriptor
structures to reflect pass-2 hw implementation.

Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>