[XS] Change in coreboot[main]: arch/x86: Clarify help text for 64-bit support

[Subrata Banik (Code Review)]

Attention is currently required from: Angel Pons, Arthur Heymans, Julius Werner, Jérémy Compostella, Lean Sheng Tan, Nico Huber.

Subrata Banik has posted comments on this change by Subrata Banik. ( https://review.coreboot.org/c/coreboot/+/83009?usp=email )

Change subject: arch/x86: Clarify help text for 64-bit support
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Patch Set 2:

(1 comment)

Commit Message:

https://review.coreboot.org/c/coreboot/+/83009/comment/66a097d8_f6d77327?usp... :
PS1, Line 18: "HAVE_X86_64_SUPPORT" Kconfig help text.
> Well, the commit message should be sync'ed / just say so. Dropping
> the "experimental" has nothing to do with Rex.

Rex is the first platform as per my understanding which has enabled end-to-end x86_64 support (from coreboot till payload/libpayload). Hence, I was using rex as the reference to call out that x86_64 support in coreboot is now well matured where we are using 64-bit FSP, 64-bit coreboot and 64-bit libpayload as well.

But I understand your point hence, edited the commit msg.