ALSA: hda - Merge HP mute-LED status callback on both IDT 92HD7x and 8x codecs

Merge the mute-LED status callback function for both IDT 92HD7x and 8x
codecs to one function.  Also it's changed to check all DACs, and called
in the initialization to sync with the current status.

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