[WIN32] hook up CAEFactory::DeviceChange() to audio device changes

Not sure if this is a feature for G+1 or just an addition as https://github.com/xbmc/xbmc/commit/994210e14975df65b38364b1df3f4f3f3bce15a1 went also in.
As the title says it calls CAEFactory::DeviceChange() when an audio device change occurs. I dunno if the callback register in XBMC_PC is the right place or if there's a better place. Putting it in the sinks would make us blind to device changes during ae idle.