[M] Change in coreboot[master]: mb/google/rex: Update Rex Flash Layout to fit WP_RO within 4MB

[Paul Menzel (Code Review)]

Attention is currently required from: Tarun Tuli, Subrata Banik, Kapil Porwal.

Paul Menzel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/74229 )

Change subject: mb/google/rex: Update Rex Flash Layout to fit WP_RO within 4MB
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Patch Set 3:

(3 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/74229/comment/7f934193_14de6de9 
PS1, Line 9: This patch updates the Rex flash layout to optimize WP_RO to 4MB.
> > Why is that done? […]

The board was apparently added with 8 MB, so why is it too big now? What optimization is done?

https://review.coreboot.org/c/coreboot/+/74229/comment/ee97b93f_f6c87c7f 
PS1, Line 9: This patch updates the Rex flash layout to optimize WP_RO to 4MB.
           : 
           : Changes for chromeos.fmd:
           : 
           : SI_BIOS:
           :      RW_SECTION_A/B: Reduce to 7MB.
           :      RW_LEGACY: Reduce to 1MB.
           :      RW_MISC: Increased to 1MB.
           :      RW_UNUSED: 3MB (reserved)
           :      WP_RO: Reduce to 4MB
           : 
           : Additionally, ensure RW_SECTION_B region starts at 16MB boundary in the
           : SPI Flash.
> > Why not make it two (or three) commits? […]

I am sorry you are feeling this way.

File src/mainboard/google/rex/chromeos.fmd:

https://review.coreboot.org/c/coreboot/+/74229/comment/08c7718a_efc8cf20 
PS1, Line 7: 7M
> > > I’d make these non-functional changes a separate commit. […]

Changing 7092K to 7M is cosmetic, isn’t it?