Refactor haptic constant.

Use the constant from IExternalVibratorService.

Bug: 124318236
Test: play audio-haptic coupled file
Change-Id: Ice2ac13d0f6a6a749bb6243230524336144fa5f4
diff --git a/services/audioflinger/FastMixerState.h b/services/audioflinger/FastMixerState.h
index c27f2b7..396c797 100644
--- a/services/audioflinger/FastMixerState.h
+++ b/services/audioflinger/FastMixerState.h
@@ -49,7 +49,7 @@
     audio_format_t          mFormat;         // track format
     int                     mGeneration;     // increment when any field is assigned
     bool                    mHapticPlaybackEnabled = false; // haptic playback is enabled or not
-    AudioMixer::haptic_intensity_t mHapticIntensity = AudioMixer::HAPTIC_SCALE_NONE; // intensity of
+    AudioMixer::haptic_intensity_t mHapticIntensity = AudioMixer::HAPTIC_SCALE_MUTE; // intensity of
                                                                                      // haptic data
 };