audio: Use labs() instead of abs()

* abs() accepts ints as parameters,
  but this breaks compile since
  the times are longs, not ints
* Use labs() instead, which accepts
  longs as parameters, to fix compile

Change-Id: I8f980a78380cdae18abd5b9602e281beae3ee4d3
Signed-off-by: Paul Keith <javelinanddart@aidenswann.com>