Change in coreboot[master]: mb/google/brya: Enable display and DSP audio UPD

[Sathyanarayana Nujella (Code Review)]

Attention is currently required from: Furquan Shaikh, Sugnan Prabhu S, Paul Menzel, Subrata Banik, Sathya Prakash M R, Tim Wawrzynczak.
Sathyanarayana Nujella has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/51510 )

Change subject: mb/google/brya: Enable display and DSP audio UPD
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Patch Set 4:

(1 comment)

File src/mainboard/google/brya/variants/baseboard/devicetree.cb:

https://review.coreboot.org/c/coreboot/+/51510/comment/e2e64cdb_00e5398d 
PS4, Line 63: pLinkTmode"		= "HDA_TMODE_8T"
            : 	register "PchHdaIDispLinkFre
if not now, later stage.. please help do this:
For iDisp link mode and link frequency UPD config params -
Do not program in devicetree, instead leave it to FSP?

for e.g.
In TGL, we initially had that setting from DT and later changed. Please see this.
https://review.coreboot.org/c/coreboot/+/40263

Also, for ADL_M RVP, it has been tried and working:
https://review.coreboot.org/c/coreboot/+/51353