cxgbe(4): hw/fw headers and shared code for the Terminator 7 ASIC

This is the first of a series of commits that will add T7 support to
cxgbe. The ASIC is gen5x16 on the PCIe side and has a 400Gbps MAC on
the Ethernet side. NICs using the T7 will come in the following
variants:

• 1 x 400Gbps with QSFP-DD connector
• 2 x 200/100/40Gbps with QSFP56/QSFP28/QSFP+ connectors
• 4 x 50/25/10/1Gbps with SFP28/SFP+/SFP connectors

There are 8 general purpose ARM A72 cores available on select
SmartNIC/DPU boards.

Obtained from: Chelsio Communications
Sponsored by: Chelsio Communications

(cherry picked from commit c7b2e390de43bb2b1a5918a23310ec5464ee3787)