add back wait_for_stream_focus to C API

- audio HAL needs to wait for focus for short time
  regardless bigger timeout to prevent SurfaceFlinger
  from trying write too often.
- That can lead into burning CPU (for returning 0) or throwing
  away too quickly (for returning full size and throwing away)

bug: 25330290

(cherry picked from commit 10b4aa159e8366fe724e997bf6b0b242980f2e09)

Change-Id: Icc5c41dd241d77dd5b814da43323efa5fdcec14c
2 files changed