[L] Change in coreboot[main]: arch/io.h: Add stubs for x86 I/O port functions to other arches

[Arthur Heymans (Code Review)]

Attention is currently required from: Alper Nebi Yasak, Julius Werner, Philipp Hug, ron minnich.

Arthur Heymans has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80372?usp=email )

Change subject: arch/io.h: Add stubs for x86 I/O port functions to other arches
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Patch Set 3: Code-Review+1

(1 comment)

Commit Message:

https://review.coreboot.org/c/coreboot/+/80372/comment/81299059_0de95b58 :
PS3, Line 19: We could cover every port function call with #if CONFIG(ARCH_X86), but
            : that gets very cluttery. And it looks like it might be possible to
            : somehow access to I/O ports over MMIO, as far as I can tell from U-Boot
            : and Linux code.
The hardware often has a translator. Can you add that information as a TODO comment in the code?