ALSA: HDA: conexant support for Lenovo T520/W520

This is patch for Conexant codec of Intel HDA driver, adding new quirk
for Lenovo Thinkpad T520 and W520. Conexant autodetection works fine for
T520 (similar subsystem ID is used also in W520 model) and detects more
mixer features compared to generic (fallback) Lenovo quirk with
hardcoded options in Conexant codec.

Patch was activelly tested with Linux 3.0.4, 3.0.6 and 3.0.7 without any
problems.

Signed-off-by: Daniel Suchy <danny@danysek.cz>
Cc: <stable@kernel.org> [3.0+]
Signed-off-by: Takashi Iwai <tiwai@suse.de>