[XS] Change in coreboot[main]: mb/google/brox/var/brox: Enable Class-D calibration

[Terry Cheong (Code Review)]

Attention is currently required from: Shelley Chen, Subrata Banik, Terry Cheong.

Hello Shelley Chen, Subrata Banik, Vamshi Krishna Gopal, build bot (Jenkins),

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/82794?usp=email

to look at the new patch set (#7).

Change subject: mb/google/brox/var/brox: Enable Class-D calibration
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mb/google/brox/var/brox: Enable Class-D calibration

DC offset of class-D amplifier is 7mV in Brox which is larger than the expected 3mV.
Add a section in the verb table to enable class-D calibration based
on the updated verb table provided by Realtek in b:342506575 comment#6.

This improves the offset to be less than 1mV.

BUG=b:342506575
BRANCH=main
TEST=Verify DC offset of speaker amplier output is less than 1mV with a multimeter when \
     playing -100dB sine waves.

Change-Id: I776f5c24ce3c829cbd64840957c1431608cf2b85
Signed-off-by: Terry Cheong 
---
M src/mainboard/google/brox/variants/brox/include/variant/hda_verb.h
1 file changed, 6 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/94/82794/7