[ALSA] hda-intel: support for iMac 24'' released on 09/2006

Basic audio support for the iMac 24'' model released on 09/2006,
including
headphone jack detection with automatic speaker muting.
This iMac uses the Realtek ALC885 codec, not a Sigmatel one as in
other models.
Functionality has been tested for internal speakers, headphone and
microphone.

Signed-off-by: Nicola Fagnani <nicfagn@iol.it>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>