[AE/osxsink] - allow up to 16 channels in osx sink - fixes #15261

Conflicts:
	xbmc/cores/AudioEngine/Sinks/AESinkDARWINOSX.cpp
[ae/osxsink] - fetch multichannel or stereo channel map from ca and use this to remap channels - fixes wrong lpcm channel mapping
[AE/osxsink] - allow mapping of more then CA_MAX_CHANNELS if a channel map
was fetched - takes care of #15261