ALSA: hda - Assign proper digital I/O type for STAC/IDT

Assign the proper PCM digital I/O type (HDA_PCM_TYPE_*) for the digital
I/O on STAC/IDT codecs.  HDA_PCM_TYPE_HDMI is assigned for the HDMI I/O.

A similar framework is implemented to patch_realtek.c, but it's not
set up and still using only HDA_PCM_TYPE_SPDIF yet.

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