[osxsink] - properly set the ae device type based on either ca or heuris...

...tical criteria - fixes DisplayPort not detected as LPCM capable and maybe others.

This hopefully fixes some false decisions the former code does. We treated displayports as optical (preventing the user from doing LPCM) and we might even HDMI devices as optical because we overwrite the device type during enumeration when we find some compatible 2.0 48000 digital stream.

Bug reported here:
http://forum.xbmc.org/showthread.php?tid=188165

@jmarshallnz @fernetmenta for comments ...

gotham material