[M] Change in coreboot[main]: Documentation: Improve x86_64

[Paul Menzel (Code Review)]

Attention is currently required from: Arthur Heymans, Benjamin Doron, Felix Held, Patrick Rudolph.

Paul Menzel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/79160?usp=email )

Change subject: Documentation: Improve x86_64
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Patch Set 2: Code-Review+1

(1 comment)

Patchset:

PS2: 
Two patches would be nice.

1.  Documentation: Move x86_64 documentation to dedicated page
2.  Documentation: Update and improve x86_64

That way it’s easier to see, what was updated.