mb/prodrive/hermes/hda_verb.c: Refactor port B Vref cfg
Refactor the `get_port_b_vref_cfg()` function to only return the
variable bits of the value. The NID itself is not connected, and
the `misc` field in the verb conveys the Vref value.
Change-Id: I5108f5339c5b002403a4e5339da6d52046c8bcbe
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82395
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>