[M] Change in coreboot[main]: sio/nuvoton: Implement a common ramstage ACPI LDN helper

[Nico Huber (Code Review)]

Attention is currently required from: Keith Hui, Paul Menzel.

Nico Huber has posted comments on this change by Keith Hui. ( https://review.coreboot.org/c/coreboot/+/82632?usp=email )

Change subject: sio/nuvoton: Implement a common ramstage ACPI LDN helper
......................................................................

Patch Set 5:

(1 comment)

Patchset:

PS5:
> Now that I think about it, in the future I'll want to make the port role swapping automatic if keybo […]

You mean pc_keyboard_init(), right? That's kind of always deprecated and disabled
by default, AIUI (payloads just do it better, except for odd situations with Linux
and quirky hardware, i.e. ThinkPad ECs). So I'd just try to implement the smallest
possible detection code and put that in LDN A. After all, you'd want this code to
work no matter if keyboard init is done in coreboot, I guess.