audio: hal: Use the elapsed time only if last_write_time_us is valid

If last_write_time_us is zero, that means the output is first one.
So we don't need to subtract the time.

Bug: 33764682
Change-Id: If4261b90dc7b05cbe973aa68a8b965990b65b28d
1 file changed
tree: f95befe0a48ecdfef2d041119bf41928d359370e
  1. hal/
  2. legacy/
  3. post_proc/
  4. visualizer/
  5. voice_processing/
  6. Android.mk