Change in coreboot[master]: amdfwtool: Use relative address for EFS gen2

[Bao Zheng (Code Review)]

Attention is currently required from: Martin Roth, Marshall Dawson, Kangheui Won, Paul Menzel, Zheng Bao, Eric Peers, Karthikeyan Ramasubramanian, Felix Held.
Bao Zheng has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/56438 )

Change subject: amdfwtool: Use relative address for EFS gen2
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Patch Set 15:

(2 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/56438/comment/8f2ac213_8ebb4f98 
PS2, Line 9: The second generation EFS (offset 0x24[0]=0) uses
           : "binary relative" offsets and not "x86 physical
           : MMIO address" like gen1.
           : 
           : Chips like Cezanne can run in both cases, so no problem
           : comes up so far.
           : 
           : TODO: Need to fix the problem in psp_verstage.
> Eric: this patch basically implements what the spec #55758 says. […]

Done

https://review.coreboot.org/c/coreboot/+/56438/comment/e7af09cf_2f3136e6 
PS2, Line 19: Test=Majolica (Cezanne)
> need to test on guybrush as well since Majolica doesn't have the TPM that guybrush does.

Tested on this change.
https://review.coreboot.org/c/coreboot/+/58316

Done.