[L] Change in coreboot[main]: util/ifdtool: Add new cmdline to enable GPR0 protection

[Reka Norman (Code Review)]

Attention is currently required from: Stefan Reinauer, Subrata Banik.

Reka Norman has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80235?usp=email )

Change subject: util/ifdtool: Add new cmdline to enable GPR0 protection
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Patch Set 4:

(7 comments)

Patchset:

PS4: 
Looks good with a few nits.

File util/ifdtool/ifdtool.c:

https://review.coreboot.org/c/coreboot/+/80235/comment/2b625ec6_f4e29637 :
PS4, Line 47: union gprd_info
nit: just `union gprd`? (I think you missed my previous comment about this)

https://review.coreboot.org/c/coreboot/+/80235/comment/4aa301cd_d70634f4 :
PS4, Line 50: 0-15
`0-14` (or just drop this since it's implied from the bitfield)

https://review.coreboot.org/c/coreboot/+/80235/comment/0825e1e6_f478a9ef :
PS4, Line 50: 		 * Start Address: bit 0-15 of the GPRD represents the protected region start address,
nit: limit to 100 chars? Not sure if there's a guideline, but the rest of the file is under 100.

https://review.coreboot.org/c/coreboot/+/80235/comment/f3a41287_1d0f31d9 :
PS4, Line 1676: 	fpt++; /* Move to the next structure which is FPT sub-partition entries */
              : 	struct cse_fpt_sub_part *fpt_sub_part = (struct cse_fpt_sub_part *)fpt;
nit: this could just be `struct cse_fpt_sub_part *fpt_sub_part = (struct cse_fpt_sub_part *)(fpt + 1)`

https://review.coreboot.org/c/coreboot/+/80235/comment/e8ea5c59_5f5deaf7 :
PS4, Line 1685: continue
Don't need this

https://review.coreboot.org/c/coreboot/+/80235/comment/ede69e06_5eaf2687 :
PS4, Line 1776: 
nit: `gprd.data.read_protect_en = 0`. Since you're reusing gprd from above there's a chance it could be set.