Change in coreboot[master]: device/pnp,util/sconfig: introduce and use `REG8` resource type

[Michael Niewöhner (Code Review)]

Michael Niewöhner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/48925 )

Change subject: device/pnp,util/sconfig: introduce and use `REG8` resource type
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Patch Set 8:
> Patch Set 8:
>
> since MSC0-MSCE only cover a few possible registers that might need to be written, I don't see much reason to have special cases for MSC0-MSCE. not sure if the sio driver providing a mask of possible writable registers provides any value, it might however create some confusion that some register writes have some special handling in the sio driver and some not

that's what I actually mean, yes. there's no mask, we would need to implement/define them all