[M] Change in coreboot[main]: 3rdparty/open-power-signing-utils: add SecureBoot utility for OpenPOWER

[Sergii Dmytruk (Code Review)]

Attention is currently required from: Arthur Heymans, Elyes Haouas, Krystian Hebel.

Sergii Dmytruk has posted comments on this change by Sergii Dmytruk. ( https://review.coreboot.org/c/coreboot/+/67065?usp=email )

Change subject: 3rdparty/open-power-signing-utils: add SecureBoot utility for OpenPOWER
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Patch Set 38:

(2 comments)

Patchset:

PS38:
> Talos II firmware enabled secure boot in 2.10 by default [1], […]

What's an OS key?  The one they call a "software key"?  So just always using `sw_key_p.key` instead of reusing `hw_key_a.key` in that role by default (don't know why it was done that way)?

File 3rdparty/open-power-signing-utils:

https://review.coreboot.org/c/coreboot/+/67065/comment/fb82eea2_c1e90d82?usp... :
PS38, Line 1: 591c8f53482243626901e1cc8a4ae321f314040d
> why not "591c8f53482243626901e1cc8a4ae321f314040d" ?

This isn't an actual file's content, it's a textual representation of a git object.