[M] Change in coreboot[master]: soc/amd: Remove unsupported DPTC tablet mode settings

[Raul Rangel (Code Review)]

Attention is currently required from: Jason Glenesk, Matt DeVillier, Martin Roth, Tim Van Patten, Fred Reitberger, Felix Held.

Raul Rangel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/67181 )

Change subject: soc/amd: Remove unsupported DPTC tablet mode settings
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Patch Set 7:

(1 comment)

Patchset:

PS5:
> Currently, no tablet mode DPTC values exist for these SOCs in the device tree, so the feature can't be enabled for anything anyway. This removes the possibility of enabling a broken feature.

Well you would set the values and set `dptc_enable = true`. So I wouldn't say it's enabling a broken feature, it just needs to be configured.
> If this is the case, maybe tablet mode shouldn't be an SOC feature and should be moved into the mainboards for boards that do support it?

Well here's the dirty little secret, the `.asl` is looking at Chrome EC specific registers to determine the states. So it really is a Google specific feature right now. We just don't have a good spot for chromeos/amd code that is shared between SoCs.