[M] Change in coreboot[master]: soc/intel: Use common codeflow for MP init

[Arthur Heymans (Code Review)]

Attention is currently required from: Tarun Tuli, Subrata Banik, Johnny Lin, Dinesh Gehlot, David Hendricks, Kapil Porwal, Christian Walter, Werner Zeh, Tim Chu.

Arthur Heymans has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/72604 )

Change subject: soc/intel: Use common codeflow for MP init
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Patch Set 3:

(1 comment)

Patchset:

PS3:
> CPU frequency seems to be dropping with the changes. On ToT bin it was ~1200MHz but it drops to ~400MHz for few cases with changes for rex.
>
> Steps to reproduce:
> Check CPU information from AP console.
> Compare all occurrence of key word "CPU MHz"
> localhost ~ cat /proc/cpuinfo

That's really strange as the bootflow is pretty much identical. No new code is run.
Are you sure CPU freq change is not to be expected? You can see what power states are expected with powertop. cpuinfo just shows the current cpu freq which depends on the load.