[PPC,SOUND] Fix audio gpio state detection

[Benjamin Herrenschmidt]

> > This (sort of) breaks PowerMac3,4 (69 (PowerMac G4 Silver)). I have to
> > force it on up to now, but with this patch the internal speaker will not
> > work with or without my patch to force it on.
> 
> But the patch fixes also my PowerBook4,1, I dont have to toggle the headphone
> once to get the built-in speakers enabled.
> Looks like 2.6.16 stuff, but its been broken for so long now...

What is the status of Ben's latest stuff ?

Ben.