Merge branch 'tools-ynl-fill-in-some-gaps-of-ethtool-spec'

Stanislav Fomichev says:

====================
tools: ynl: fill in some gaps of ethtool spec

I was trying to fill in the spec while exploring ethtool API for some
related work. I don't think I'll have the patience to fill in the rest,
so decided to share whatever I currently have.

Patches 1-2 add the be16 + spec.
Patches 3-4 implement an ethtool-like python tool to test the spec.

Patches 3-4 are there because it felt more fun do the tool instead
of writing the actual tests; feel free to drop it; sharing mostly
to show that the spec is not a complete nonsense.

The spec is not 100% complete, see patch 2 for what's missing.
I was hoping to finish the stats-get message, but I'm too dump
to implement bitmask marshaling (multi-attr).
====================

Link: https://lore.kernel.org/r/20230329221655.708489-1-sdf@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>