ALSA: hda - iMac 9,1 sound patch.

This is an updated patch for the Apple iMac 9,1 model to add sound.
Original patch posted here:
http://article.gmane.org/gmane.linux.alsa.devel/61361/match=

I have been using this patch for a while now
and have to say it works vary well, except for a few minor 
things:

	With the iMac 24-inch 3.06GHz Intel Core 2 Duo
	everything seems to be working as it should,
        although I have not looked into the microphone
	(never really use one, nor have any apps to test,
	my guess is it doesn't work, or I never figured out how
	to get it to work).

	With the iMac 24-inch 2.66GHz Intel Core 2 Duo
	everything is the same as with the above machine 
	except I'm hearing a light scratchy/distortion noise
	come out of the speakers when using headphones(above machine
	does not do this).

Other than that the sound level is great(especially with good Dj headphones).

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Tested-by:     Justin P. Mattock <justinmattock@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 9000cd8..e93afff 100644
--- a/Documentation/sound/alsa/HD-Audio-Models.txt
+++ b/Documentation/sound/alsa/HD-Audio-Models.txt
@@ -126,6 +126,7 @@
   mb5		Macbook 5,1
   mbp3		Macbook Pro rev3
   imac24	iMac 24'' with jack detection
+  imac91	iMac 9,1
   w2jc		ASUS W2JC
   3stack-2ch-dig	3-jack with SPDIF I/O (ALC883)
   alc883-6stack-dig	6-jack digital with SPDIF I/O (ALC883)