CHROMIUM: ALSA: hda: Add fixup for alex model

CHROMIUM: ALSA: hda: Add fixup for alex model

create fixup function for the alex model and override amp capabilities
for NID 0x2 to remove clipping of audio to built-in speakers

related CL(s):
http://codereview.chromium.org/6544026/
http://codereview.chromium.org/6469065/

BUG=chrome-os-partner:2273
TEST=manual,
1. Build kernel and install on device
2. Edit /etc/modprobe.d/alsa.conf to include 'options snd_hda_intel model=alex'
3. Reboot
4. shell>amixer -c 0 sget Speaker | grep -i limit
   Should produce 'Limits: Playback 0 - N' where N < 64 (max gain)

Change-Id: Ib4efa3db95955e95421ec55bc77699d6a9faeb62
Signed-off-by: Todd Broch <tbroch@chromium.org>
Reviewed-on: http://gerrit.chromium.org/gerrit/3140
Reviewed-by: Olof Johansson <olofj@chromium.org>
Conflicts:

	sound/pci/hda/patch_realtek.c
[anush: fixup for 3.4]
Signed-off-by: Anush Elangovan <anush@chromium.org>