[L] Change in coreboot[master]: [RFC] Pull libgfxinit in early romstage

[Jeremy Compostella (Code Review)]

Attention is currently required from: Nico Huber, Tarun Tuli, Martin L Roth, Jérémy Compostella, Angel Pons, Arthur Heymans, Kyösti Mälkki, Andrey Petrov.

Jeremy Compostella has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/69757 )

Change subject: [RFC] Pull libgfxinit in early romstage
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Patch Set 3:

(1 comment)

File src/arch/x86/car.ld:

https://review.coreboot.org/c/coreboot/+/69757/comment/823e5c0b_6348692e 
PS1, Line 122:
> My understanding is that global **initialized** variable are not permitted in cache-as-ram. […]

I could not find a way to test a symbol value from the linker script therefor I was unable to move the zero data symbols to the .bss automatically.

However, switching to the libhwbase static mmio driver suppresses the three problematic symbols.

With a few extra changes (https://review.coreboot.org/c/libgfxinit/+/69855, https://review.coreboot.org/c/libhwbase/+/69854) which I am sure you will some concerns with I am able to get something relatively acceptable from a linker script perspective (https://review.coreboot.org/c/coreboot/+/69757/3/src/arch/x86/car.ld).