audio_format: remove the reverse_endian attribute

Eliminate support for reverse endian samples from the MPD core.  This
moves a lot of complexity to the plugins that really need it (only
ALSA and CDIO currently).

src/decoder_api.c

@@ -56,9 +56,6 @@ decoder_initialized(struct decoder *decoder,
 
 	dc->in_audio_format = *audio_format;
 	getOutputAudioFormat(audio_format, &dc->out_audio_format);
-	/* force host byte order, even if the decoder supplies reverse
-	   endian */
-	dc->out_audio_format.reverse_endian = false;
 
 	dc->seekable = seekable;
 	dc->total_time = total_time;