[ALSA] ac97 - fix malfunctioning mixer controls for AD1985

This patch replaces the 'V_REFOUT Enable' mixer switch control
with a listbox control for the AD1985 CODEC.
Previous patch 'AD1888 mixer controls for DC mode' added
controls that were propogated to multiple codecs.  For the
AD1985 codec, the bits VREFH and VREFD function differently,
preventing the 'V_REFOUT Enable' control from setting V_REFOUT
to Hi-Z.
This patch also corrects an issue in which register bits relating
to mixer controls 'Surround Jack Mode' and 'Channel Mode'.
The register bits controlled by these controls were being set
at boot time to states inconsistent with the stored values of
these controls.

Signed-off-by: Randy Cushman <rcushman_linux@earthlink.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>