ALSA: hda - Add support for the new 27 inch IMacs

With the attached patch I am able to use the sound on a new IMac 27.
What works:

*) Internal speakers
*) Internal microphone
*) Headphone

I don't have an external mic or a SPDIF device to test the rest.

Signed-off-by: Rafael Avila de Espindola <rafael.espindola@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/Documentation/sound/alsa/HD-Audio-Models.txt b/Documentation/sound/alsa/HD-Audio-Models.txt
index e93afff..e72cee9 100644
--- a/Documentation/sound/alsa/HD-Audio-Models.txt
+++ b/Documentation/sound/alsa/HD-Audio-Models.txt
@@ -403,4 +403,5 @@
 Cirrus Logic CS4206/4207
 ========================
   mbp55		MacBook Pro 5,5
+  imac27	IMac 27 Inch
   auto		BIOS setup (default)