Change in coreboot[master]: soc/intel/alderlake: Move INTEL_CAR_NEM selection from SoC to mainboard

[Subrata Banik (Code Review)]

Attention is currently required from: Furquan Shaikh, Paul Menzel, Tim Wawrzynczak, Meera Ravindranath, Patrick Rudolph.
Subrata Banik has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/56993 )

Change subject: soc/intel/alderlake: Move INTEL_CAR_NEM selection from SoC to mainboard
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Patch Set 1:

(1 comment)

Commit Message:

https://review.coreboot.org/c/coreboot/+/56993/comment/f1bf2e4e_be7393a6 
PS1, Line 11: feature on OEM/ODM reference designs.
> Were problems observed?

its kind of precaution steps so we don't want to run into the issue and be in catching situation.