ALSA: hda - Fix conflict of mixer controls on Sony VAIO VGN-AR71S

The recent update enabled the model=sony-assamd for all ALC262 with
PCI SSID 104d:90xx.  But this includes the VAIO VGN-AR* that has the
primary codec of STAC92xx and the secondary ALC262 as a slave
digital-only codec.  For this device, the model=auto must be chosen
to work properly.

Signed-off-by: Takashi Iwai <tiwai@suse.de>