Change in coreboot[master]: soc/intel/denverton_ns: Always enable SpeedStep

[Paul Menzel (Code Review)]

Attention is currently required from: Дмитрий Понаморев, Mariusz Szafrański, Suresh Bellampalli, Vanessa Eusebio, Angel Pons, Michal Motyl, Patrick Rudolph, King Sumo.
Paul Menzel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/57669 )

Change subject: soc/intel/denverton_ns: Always enable SpeedStep
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Patch Set 3:

(2 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/57669/comment/11607574_6871ed8b 
PS2, Line 12:
> Оperating system cannot change the frequency. Clock is stuck at 800MHz. […]

Please add that to the commit message. Also, can the OS lower the speed again to 800 MHz?

Commit Message:

https://review.coreboot.org/c/coreboot/+/57669/comment/461ddfff_fcf3f36a 
PS3, Line 9: When SpeedStep is disabled on an Atom C3538, the maximum CPU clock
           : speed is limited to 800 MHz.
This is the symptom. Please elaborate, why `enable_turbo()` seems to fail, causing the if condition to fail.