audio_hw: clean up mmap input delay

Set default offset to zero if no property used.
Remove unneeded FIXME.
Improve comments.
Cleanup adding of offset.

Bug: 122680738
Test: adb shell aaudio_loopback -tm -s20
Change-Id: Idd85f8978443e036ba4c5fb6440320a8578a74fd
1 file changed
tree: 180d3f0bcac8f5df3fc20abd5d8ddca46ea7423d
  1. hal/
  2. legacy/
  3. post_proc/
  4. visualizer/
  5. voice_processing/
  6. Android.mk
  7. OWNERS