Fix issue 1745312: Various cleanups in media framework

AudioTrack, AudioRecord:
  - remove useless mAudioFlinger member of AudioTrack and AudioRecord.
  - signal cblk.cv condition in stop() method to speed up stop completion.
  - extend wait condition timeout in obtainBuffer() when waitCount is -1 to avoid waking up callback thread unnecessarily

AudioFlinger:
  - remove some warnings in AudioFlinger.cpp.
  - remove function AudioFlinger::MixerThread::removetrack_l()  as its content is never executed.
  - remove useless call to setMasterVolume in AudioFlinger::handleForcedSpeakerRoute().
  - Offset VOICE_CALL stream volume to reflect actual volume that is never 0 in hardware (this fix has been made in the open source): 0.01 + v * 0.99.

AudioSystem.java:
  - correct typo in comment

IAudioflinger, IAudioFlingerClient:
  - make AudioFlinger binder interfaces used for callbacks ONEWAY.

AudioHardwareInterface:
  - correct routeStrings[] table in AudioHardwareInteface.cpp