Change in coreboot[master]: soc/intel: drop unneeded ISST configuration code

[Michael Niewöhner (Code Review)]

Michael Niewöhner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/46460 )

Change subject: soc/intel: drop unneeded ISST configuration code
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Patch Set 2:
> Patch Set 2:
>
> IMO a cleaner approach would be to move the code to a function in the MSR common block, switch any boards disabling ISST to use the function directly vs setting DT register, and then dropping from the SoC code

Cleaner? How could useless code be cleaner than no code?