[M] Change in coreboot[master]: common/acpi/dptc: Implement DTTS Proposal

[Raul Rangel (Code Review)]

Attention is currently required from: Jason Nien, EricKY Cheng, Matt DeVillier, Martin Roth, Tim Van Patten, Eric Peers, Jason Glenesk, Caveh Jalali, Tim Wawrzynczak, Fred Reitberger, Karthikeyan Ramasubramanian, Boris Mittelberg, Felix Held.

Raul Rangel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/68471 )

Change subject: common/acpi/dptc: Implement DTTS Proposal
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Patch Set 30:

(4 comments)

File src/mainboard/google/skyrim/dsdt.asl:

https://review.coreboot.org/c/coreboot/+/68471/comment/024dc056_6986acbb 
PS30, Line 18: variants/winterhold/DTTS.asl
Add the following include line here:
https://review.coreboot.org/plugins/gitiles/coreboot/+/refs/heads/master/src...

```
CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/variants/$(VARIANT_DIR)/acpi
```

Then just do `#include <dtts.asl>`

File src/mainboard/google/skyrim/variants/winterhold/DTTS.asl:

PS30: 
I think you can move this into "mb/google/skyrim/variants/winterhold/acpi/dtts.asl"

https://review.coreboot.org/c/coreboot/+/68471/comment/a4db1f67_8b0ac658 
PS30, Line 45: LGreaterEqual
Just use `>=`

https://review.coreboot.org/c/coreboot/+/68471/comment/f0c7fe19_94d00887 
PS30, Line 46: )
nit: don't think you need the extra `()`