[M] Change in coreboot[main]: Add MTCL function to ACPI SSDT tables

[Nico Huber (Code Review)]

Attention is currently required from: Cliff Huang, David Ruth, Lance Zhao, Subrata Banik, Subrata Banik, Tim Wawrzynczak.

Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80170?usp=email )

Change subject: Add MTCL function to ACPI SSDT tables
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Patch Set 14: Code-Review+1

(4 comments)

Patchset:

PS14: 
One (hopefully) last thing: As USE_MTCL is `default n`, `mtcl.c` isn't covered
by the CI. You can enable it by placing a config file (for any board you like)
in `configs/` with `CONFIG_USE_MTCL=y`. The file name needs to match the board's
Kconfig name (in lowercase), e.g. for CONFIG_BOARD_GOOGLE_REEF, files matching
`config.google_reef*` are considered. (You could also add it to an existing
file.)

File src/drivers/wifi/generic/mtcl.c:

https://review.coreboot.org/c/coreboot/+/80170/comment/bf34efcc_8a301a8b :
PS14, Line 9:  WIFI_MTCL_CBFS_DEFAULT_FILENAME "wifi_mtcl.hex"
> nit: can we use `WIFI_MTCL_CBFS_FILEPATH` config directly here ? (instead of defining a new macro)? […]

This is the filename inside CBFS, as hardcoded in the Makefile.mk, isn't it?
The Kconfig is for the file path on the build host.

https://review.coreboot.org/c/coreboot/+/80170/comment/00e4834e_1257ecd1 :
PS14, Line 10: #define MAX_VERSION 2
             : #define MAX_SUPPORT_STATE 2
             : #define COUNTRY_LIST_SIZE 6
             : #define NAME_SIZE 4
             : #define MTCL_NAME "MTCL"
> nit: wondering if moving these macros into mtcl.h makes sense. […]

The API user doesn't need to know this, so I'd say no.

File src/include/mtcl.h:

PS14: 
Could move this to the wifi/generic/ driver, as it's only used there now.