[M] Change in coreboot[main]: cpu/x86/64bit: Install extended page tables in BSS

[Maximilian Brune (Code Review)]

Attention is currently required from: Christian Walter, Intel coreboot Reviewers, Johnny Lin, Jonathan Zhang, Jérémy Compostella, Patrick Rudolph, Tim Chu.

Maximilian Brune has posted comments on this change by Patrick Rudolph. ( https://review.coreboot.org/c/coreboot/+/85806?usp=email )

Change subject: cpu/x86/64bit: Install extended page tables in BSS
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Patch Set 6:

(1 comment)

Patchset:

PS6:
> `CPU_PT_ROM_MAP_GB` affects all stages. […]

Considering that we use 1GB pages for almost all platforms (especially the more recent ones) we don't really save much space do we? So it doesn't really have an effect on any platform besides QEMU maybe. All other platforms that need 2MB pages for are already ~10 year old and don't have this much RAM anyway.