ALSA: HDA: Use model=auto for Thinkpad T510

The user reports that model=auto works fine for him. Using
model=auto bring in new features such as jack detection notification
to userspace.

Alsa info is available at http://paste.ubuntu.com/805351/



Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>