cxgbe: Support for NIC KTLS transmit on T7 adapters.

Unlike NIC KTLS support on T6, T7 is able to reuse the existing TSO
functionality directly, including trimming the output of the crypto
engine before it is passed on to TSO. This is much simpler and does
not require the use of bypass pseudo-connections in the TOE engine.
Among other things this permits arbitrary TCP options (including the
full range of possible TCP timestamp values) while also avoiding
various edge cases where parts of a requested TCP packet could not
always be transmitted (e.g. partial trailers). This implementation
also permits NIC KTLS to be used in parallel with TOE.

This version does not yet support connections over a VF (specifically
the ktls_tunnel_packet function needs to handle the VF work request),
nor does it support VxLAN offload.

MFC after: 3 days
Sponsored by: Chelsio Communications