[AE/osxsink] - fix optical usb devices with > 2 channels

there are usb devices which are basically optical devices but they have also formats with > 2 channels - mark any passthrough devices which are not DisplayPort and not HDMI as optical (not only the ones with 2 channels max) - fixes missing passthrough options for those devices.

Logfile from such a device:

http://xbmclogs.com/show.php?id=234214

Still waiting for feedback but i guess the 6 channel formats are some analog outputs or so. @fernetmenta - not quiet sure if treating such devices as optical is a good idea - or if we better should treat them as HDMI?

Jenkins was fine:

http://jenkins.xbmc.org/job/XBMC-OSX-64/1298/