[L] Change in coreboot[main]: mb/dell: Add OptiPlex 7020/9020 port

[Leah Rowe (Code Review)]

Attention is currently required from: Arthur Heymans, Michael Büchler, Nicholas Chin, Nico Huber, Paul Menzel, ilikenwf, nat ✨.

Leah Rowe has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/55232?usp=email )

Change subject: mb/dell: Add OptiPlex 7020/9020 port
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Patch Set 33:

(1 comment)

Patchset:

PS32:
> edit, to be clear: mate knows of these issues but other readers don't. […]

Also:

the pwm issue doesn't affect safety on the default i3/i5 CPUs that come on these machines, but can be problematic when upgrading to a much hotter CPU. i have an i7-4790k (90w TDP!) in mine

i got it running stable, on sff, but airflow is quite inadequate by default. i replaced all the fans and i hardwire them to run at a higher speed, to get around the pwm issue