google/asuka: Add as a variant of glados

google/asuka: Add as a variant of glados

Add google/asuka (Dell Chromebook 13 3380) as a variant of
glados Skylake reference board:
- add asuka-specific DPTF, EC config, GPIO config, Kconfig,
    NHLT config, PEI data, VBT, SPD data, and devicetree

Adapted from Chromium branch firmware-glados-7820.B, commit
b0c3efe54d877246d07f2467b2dff51cc30348fa [soc/intel/skylake: Enable VMX]

Test: build/boot google/asuka, verify correct functionality

Change-Id: I591578fea2514a28c75177835807c3f250904577
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/27421
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Youness Alaoui <snifikino@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>