aaudio: minor cleanup in clock model

Init mMaxMeasuredLatenessNanos
Use default destructor.

Bug: 137009840
Test: atest CtsNativeMediaAAudioTestCases
Change-Id: Ia9b42e4754047f5e87205c4adbc3329a1b96e74b
diff --git a/media/libaaudio/src/client/IsochronousClockModel.h b/media/libaaudio/src/client/IsochronousClockModel.h
index 40f066b..6280013 100644
--- a/media/libaaudio/src/client/IsochronousClockModel.h
+++ b/media/libaaudio/src/client/IsochronousClockModel.h
@@ -35,7 +35,7 @@
 
 public:
     IsochronousClockModel();
-    virtual ~IsochronousClockModel();
+    virtual ~IsochronousClockModel() = default;
 
     void start(int64_t nanoTime);
     void stop(int64_t nanoTime);
@@ -130,6 +130,7 @@
 private:
 
     int32_t getLateTimeOffsetNanos() const;
+    void update();
 
     enum clock_model_state_t {
         STATE_STOPPED,
@@ -164,7 +165,6 @@
     // distribution of timestamps relative to earliest
     std::unique_ptr<android::audio_utils::Histogram>   mHistogramMicros;
 
-    void update();
 };
 
 } /* namespace aaudio */