Support multichannel sounds in bootanim am: db90897b

    // configure audio source

    SLDataLocator_AndroidSimpleBufferQueue loc_bufq = {SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE, 1};

    // Determine channelMask from num_channels

    SLuint32 channelMask;

    switch (chunkFormat->num_channels) {

        case 1:

            channelMask = SL_SPEAKER_FRONT_CENTER;

            break;

        case 2:

            channelMask = SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT;

            break;

        default:

            // Default of 0 will derive mask from num_channels and log a warning.

            channelMask = 0;

    }

    SLDataFormat_PCM format_pcm = {

        SL_DATAFORMAT_PCM,

        chunkFormat->num_channels,

        chunkFormat->sample_rate * 1000,  // convert to milliHz

        chunkFormat->bits_per_sample,

        16,

        SL_SPEAKER_FRONT_CENTER,

        channelMask,

        SL_BYTEORDER_LITTLEENDIAN

    };

    SLDataSource audioSrc = {&loc_bufq, &format_pcm};