codec during initialization. This code mirrors the reset code used on
the VIA82c686 and fixes a codec initialization failure (SoundMAX
AD1885) reported by Matthias Schuendehuette.
o Make DXS3 the primary playback channel. It may be the only
universally supported channel with the assorted revisions of this
chipset.
o Add sysctl and handler for enabling s/pdif output from DXS3.