Change in coreboot[master]: mb/clevo/tgl-u: add new board L14xMU

[Arthur Heymans (Code Review)]

Attention is currently required from: Felix Singer, Nico Huber, Michał Żygowski, Michał Kopeć, Paul Menzel, Angel Pons, Michael Niewöhner.
Arthur Heymans has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/59548 )

Change subject: mb/clevo/tgl-u: add new board L14xMU
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Patch Set 15: Code-Review+2

(1 comment)

File src/mainboard/clevo/tgl-u/variants/l140mu/devicetree.cb:

https://review.coreboot.org/c/coreboot/+/59548/comment/6f4469c2_e632e70d 
PS14, Line 191: 		device ref peg on
> why? it's a SSD slot like pcie_rp9, so grouping them makes more sense to me

I guess it's for the lower pci device number? With references instead of raw numbers I think it's fine to have them grouped a bit differently?