[M] Change in coreboot[master]: payloads/edk2: Separate the build target and repository

[Lean Sheng Tan (Code Review)]

Attention is currently required from: Sean Rhodes, Martin L Roth, Matt DeVillier, Stefan Reinauer.

Lean Sheng Tan has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/66080 )

Change subject: payloads/edk2: Separate the build target and repository
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Patch Set 27:

(1 comment)

Patchset:

PS27: 
I like the structure of this approach, more neat and understandable, but still I will try to avoid to have another fork of edk2 repo again for UPL, as it will create extra discrepancies and maintenance burden. The main goal should be getting the fix merged into edk2 main repo and platform specific changes into forked edk2-platforms.