Use audio_channel_mask_t for channel mask

Change-Id: I1c1896da48983aa9f1462a4b471f910498816f60
diff --git a/libvideoeditor/lvpp/VideoEditorAudioPlayer.cpp b/libvideoeditor/lvpp/VideoEditorAudioPlayer.cpp
index 797686c..c111ba8 100755
--- a/libvideoeditor/lvpp/VideoEditorAudioPlayer.cpp
+++ b/libvideoeditor/lvpp/VideoEditorAudioPlayer.cpp
@@ -534,9 +534,7 @@
     } else {
         mAudioTrack = new AudioTrack(
                 AUDIO_STREAM_MUSIC, mSampleRate, AUDIO_FORMAT_PCM_16_BIT,
-                (numChannels == 2)
-                    ? AUDIO_CHANNEL_OUT_STEREO
-                    : AUDIO_CHANNEL_OUT_MONO,
+                audio_channel_out_mask_from_count(numChannels),
                 0, AUDIO_OUTPUT_FLAG_NONE, &AudioCallback, this, 0);
 
         if ((err = mAudioTrack->initCheck()) != OK) {