Headphone support on Thinkpad T430s

Dear list,

please see a patch to enable proper headphone support on Thinkpad T430s 
models. The quirk uses the same logic as the recent patch to CURRENT to 
enable some other Thinkpad models. Unfortunately, I cannot comment if 
this will work for other models (such as the regular T430) as well, 
therefore I used the T430S identifier.

Hope someone can commit this,

Johannes