[M] Change in coreboot[master]: WIP acpi: Add SPCR table

[Nico Huber (Code Review)]

Attention is currently required from: Arthur Heymans, Benjamin Doron, Lance Zhao, Tim Wawrzynczak.

Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/75685?usp=email )

Change subject: WIP acpi: Add SPCR table
......................................................................

Patch Set 3:

(2 comments)

File src/acpi/acpi.c:

https://review.coreboot.org/c/coreboot/+/75685/comment/78c08d6c_ccaa9814 :
PS3, Line 1842: 	/* 16550 compatible, TODO do we need others? */
Maybe:
```
if (!CONFIG(CONSOLE_SERIAL))
       return;
```

https://review.coreboot.org/c/coreboot/+/75685/comment/627b025a_7d63553b :
PS3, Line 1870: 	/* TODO: provide callback for IRQ on non standard ports*/
Would it be bad not to use an IRQ at all?