HDMI-CEC: Add S/PDIF type to absolute volume device allowlist

When outputting sound via S/PDIF, volume control should be also
available from the TV with <User Control Pressed>. Currently, we
only allows for ARC + ERAC devices.

Test: verified by vendor
Bug: b/400832673
Flag: EXEMPT Bugfix only
Change-Id: I02778e6f64d921acb3be4e52702a4a56b6477ff5