Reduce log messages on AudioFlinger throttle

Bug: 21858740
Change-Id: I8f291b64c1033867bb57ffceaa3b7d94aa998715
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index 4ebe615..b12b091 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -614,6 +614,8 @@
     size_t                          mNormalFrameCount;  // normal mixer and effects
 
     bool                            mThreadThrottle;     // throttle the thread processing
+    uint32_t                        mThreadThrottleTimeMs; // throttle time for MIXER threads
+    uint32_t                        mThreadThrottleEndMs;  // notify once per throttling
     uint32_t                        mHalfBufferMs;       // half the buffer size in milliseconds
 
     void*                           mSinkBuffer;         // frame size aligned sink buffer