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/libs/audioflinger/AudioHardwareStub.cpp b/libs/audioflinger/AudioHardwareStub.cpp
index ae391ee..ae215d1 100644
--- a/libs/audioflinger/AudioHardwareStub.cpp
+++ b/libs/audioflinger/AudioHardwareStub.cpp
@@ -158,6 +158,11 @@
     return param.toString();
 }
 
+status_t AudioStreamOutStub::getRenderPosition(uint32_t *dspFrames)
+{
+    return INVALID_OPERATION;
+}
+
 // ----------------------------------------------------------------------------
 
 status_t AudioStreamInStub::set(int *pFormat, uint32_t *pChannels, uint32_t *pRate,