mb/prodrive/hermes: Configure ALC888 port B Vref
Define a new field in the board config EEPROM layout for port B Vref.
Write port B Vref settings to unused non-volatile NID 0x12 instead of
NID 0x18, the actual port B NID. Because per-port Vref settings don't
persist after codec resets, a custom Realtek driver (ab)uses NID 0x12
to restore port B Vref after resetting the codec.
Change-Id: Iaa11ba9c74f643e94046d4983fbce65dbedd1025
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58879
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>