Change in flashrom[master]: ich_descriptors.c: Fix PCH detection for Tiger Lake

[Nico Huber (Code Review)]

Attention is currently required from: Michał Żygowski, Angel Pons.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/55577 )

Change subject: ich_descriptors.c: Fix PCH detection for Tiger Lake
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Patch Set 1:

(1 comment)

File ich_descriptors.c:

https://review.coreboot.org/c/flashrom/+/55577/comment/d335c210_a4a756ae 
PS1, Line 955: CHIPSET_300_SERIES_CANNON_POINT
> if it is not zero, then we have 300 series+ chipset
> right?

exactly.

The whole thing became a bit more complex, so I went ahead and
prepared things: CB:55647. Adding TGP on top should be much easier.
I'd say

if (ICCRIBA == 0x34)
            return 300_SERIES
    if ("CPU Soft Strap Offset from PMC Base" != 0x6c)
            warn
    return 500_series

I wonder if the field is really shifted by 2 bits or if it's
just Intels weird way to say the 2 least-significant bits are 0.