[ALSA] hda-codec - Avoid zero NID in line_out_pins[] of STAC codecs

The STAC codes adds line_out_pins[] for shared mic/line-inputs accordingly.
But, the current code may give a hole with NID=0 in some setting, which
results in an error at probe.  This patch fixes the problem.

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