Update notes for submitted changes

* libstagefright: Fix app crash during pcm offload playback
*  libstagefright: Use channel count if channel mask is zero.
* libstagefright: Fix incorrect comparison of mimetype
* audio:Avoid AudioTrackThread if Track creation fails
* audioflinger: Stop resetting compress offload streams
* Smooth out AwesomePlayer
* stagefright: add ClockEstimator API and WindowedLinearFitEstimator