[ALSA] hda-codec - Fix mic capture with generic parser

Fixed the mic capture with generic parser of hda-codec driver
- Use VREF80 for mic pins if available
- Handle multiple inputs correctly on audio-input widget node.
Confirmed on a conexant codec chip.

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