[ALSA] hda-codec - Code clean up of patch_sigmatel.c

- Remove superfluous array member in stac9205_dmic_nids[]
- Use ARRAY_SIZE() instead of hard-coded numbers

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