[ALSA] hda-codec - Add unsol_event to ALC883 Acer Aspire

Added unsol_event handling to ALC883 Acer Aspire codes.
Also, removed unneeded channel-mode mixer control from 2-ch only presets.

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