[S] Change in coreboot[master]: device/pci_rom: Set VBIOS checksum when filling VFCT table

[Felix Held (Code Review)]

Attention is currently required from: CoolStar, Eric Lai, Martin L Roth, Matt DeVillier, Matt DeVillier, Paul Menzel.

Felix Held has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/77628?usp=email )

Change subject: device/pci_rom: Set VBIOS checksum when filling VFCT table
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Patch Set 4: Code-Review+1

(1 comment)

File src/device/pci_rom.c:

https://review.coreboot.org/c/coreboot/+/77628/comment/b3498be9_7431c88f :
PS4, Line 255: 		header->VbiosContent[VFCT_VBIOS_CHECKSUM_OFFSET] = 0;
> it's zeroed out first any time it's being re-calculated. […]

when a struct is written from scratch, it gets memset to 0, so in those cases there's no need to set the checksum field to 0 a second time. here, we take an existing data structure, but need to fix up the checksum, so we need to set that field to 0 before calculating the checksum and putting that checksum in place. maybe add a comment about this?
write_le8 isn't needed, since VbiosContent is a byte array, so we can just access that array element