libstagefright: TCXO shutdown support and Misc fixes for LPA

- Add support for onPauseTimeout. This runs a 3s timer and then
  closes the Audio path. This allows TCXO shudown to happen.
- Fix the crash for pause and next song.

Change-Id: If68f53345c67d330390e2d9ecec5b8ceff3f9340
(cherry picked from commit 0dffdd9a679b32674f328bd6c6002778f61e07f0)
(cherry picked from commit 688ccbe244cc997cd4da451deaa8e8cdc60a1b55)