Fix issue 2285561: New AudioFlinger and audio driver API needed for A/V sync

Added getRenderPosition() API to IAudioFlinger to retreive number of audio frames
written by AudioFlinger to audio HAL and by DSP to DAC.

Added getRenderPosition() API to AudioHardwareInterface to retreive number of audio frames
written by DSP to DAC.

Exposed AudioTrack::getPosition() to AudioSink() to make it available to media player.

Removed excessive log in AudioHardwareGeneric.
diff --git a/include/media/MediaPlayerInterface.h b/include/media/MediaPlayerInterface.h
index 6575da6..588c51a 100644
--- a/include/media/MediaPlayerInterface.h
+++ b/include/media/MediaPlayerInterface.h
@@ -72,6 +72,7 @@
         virtual ssize_t     frameSize() const = 0;
         virtual uint32_t    latency() const = 0;
         virtual float       msecsPerFrame() const = 0;
+        virtual status_t    getPosition(uint32_t *position) = 0;
 
         // If no callback is specified, use the "write" API below to submit
         // audio data. Otherwise return a full buffer of audio data on each