Change in coreboot[master]: hp/z220_cmt_workstation: Add variant of z220_sff_workstation

[Damien Zammit (Code Review)]

Attention is currently required from: Felix Singer, Edward O'Callaghan, Angel Pons.
Damien Zammit has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/62759 )

Change subject: hp/z220_cmt_workstation: Add variant of z220_sff_workstation
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Patch Set 2:

(2 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/62759/comment/8bef782e_70e8d42a 
PS2, Line 11: The code in this commit is untested as I reworked his port into a variant.
> Please do a separate commit to turn it into a variant.

Felix: The code that works on CMT from my friend is not in the tree yet, there's no point committing an almost identical clone of the SFF board and then a new commit that removes the CMT port and converts it to a variant.  Let's just test the new variant on a CMT and verify that the SFF is still identical (?)

Patchset:

PS2: 
Thanks