Change in coreboot[master]: soc/amd/common/block/psp: Add platform secure boot support

[ritul guru (Code Review)]

Attention is currently required from: Jason Glenesk, Raul Rangel, Marshall Dawson, Paul Menzel, Angel Pons, Aamir Bohra, Fred Reitberger, Felix Held.
ritul guru has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/60968 )

Change subject: soc/amd/common/block/psp: Add platform secure boot support
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Patch Set 17:

(1 comment)

File src/soc/amd/common/block/psp/psb.c:

https://review.coreboot.org/c/coreboot/+/60968/comment/7edab526_b34c0c35 
PS14, Line 12: #define PSB_HSTI_STATUS_OFFSET	0x10998
> Would it make sense to rename those elements (in a separate commit) to have a more descriptive name? […]

description of CORE_2_PSP_MSG_38 is provided in doc#56654 under
Table 1. PSB Test and HSTI State Register Bit Fields