Merge "DownmixBufferProvider: Assign buffer frame count" into main

     mDownmixConfig.inputCfg.mask = EFFECT_CONFIG_SMP_RATE | EFFECT_CONFIG_CHANNELS |

             EFFECT_CONFIG_FORMAT | EFFECT_CONFIG_ACC_MODE;

     mDownmixConfig.outputCfg.mask = mDownmixConfig.inputCfg.mask;

     mDownmixConfig.inputCfg.buffer.frameCount = bufferFrameCount;

     mDownmixConfig.outputCfg.buffer.frameCount = bufferFrameCount;

     mInFrameSize =

             audio_bytes_per_sample(format) * audio_channel_count_from_out_mask(inputChannelMask);