configs: Set default audio sink latency to fix audio track mem failure

- Back to back playback of 192K, 8ch clips fails on BT
- AudioTrack allocates memory of 3MB for the track out of 4MB
  of heap size. This memory corresponds to the duration of 500ms.
  This much memory is not required considering the audio, BT and USB
  HAL latencies.
- Set the default audio sink latency duration to 280ms
  CRs-Fixed: 1015200

Change-Id: If8aad263e08f40768cdebad296a0c759b017a440