coreaudio: add Lsd/Rsd mapping

Could not test it.

modules/audio_output/coreaudio_common.c

@@ -629,6 +629,10 @@ AudioChannelLabelToVlcChan(AudioChannelLabel chan, bool swap_rear_surround)
                                       : AOUT_CHAN_MIDDLERIGHT;
         case kAudioChannelLabel_CenterSurround:
             return AOUT_CHAN_REARCENTER;
+        case kAudioChannelLabel_LeftSurroundDirect:
+            return AOUT_CHAN_MIDDLELEFT;
+        case kAudioChannelLabel_RightSurroundDirect:
+            return AOUT_CHAN_MIDDLERIGHT;
         default:
             return 0;
     }