Change in coreboot[master]: mb/google/skyrim: Build APCB sources into amdfw when present

[Karthik Ramasubramanian (Code Review)]

Attention is currently required from: Raul Rangel, Jon Murphy, Rob Barnes.
Karthik Ramasubramanian has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/62877 )

Change subject: mb/google/skyrim: Build APCB sources into amdfw when present
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Patch Set 2:

(2 comments)

Patchset:

PS1:
> Are we going to need to update APCB tool so we can generate these?

We have asked AMD to refer to table of SPDs outside APCB. If that can be achieved, then I dont think we need to update APCB tool. Otherwise before fanning out to more variants, we need to update APCB tool to generate these. Thankfully we can leverage APCBv3 edit tool if needed.

File src/mainboard/google/skyrim/Makefile.inc:

https://review.coreboot.org/c/coreboot/+/62877/comment/f9bc0686_21d367c0 
PS2, Line 17: SBR_D5
Renamed it to be more consistent with previous generation of mainboards eg. guybrush.