[ALSA] hda-codec - Fix the error in DAC assignment of STAC codec

The STAC codec support code has the automatic recognition of
additional side-output pins, and this may result in an error when
the assigned pin has no corresponding DAC connection.
The patch fixes the problem -- it corrects the line_outs again
without such additional pins.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>