yukawa: Fix set_voice_volume() support am: b70ebf49d8 am: 6b44fe69c7

Change-Id: Icc479ce5d268200148e3c08a70117aeed2ed7940
diff --git a/audio/audio_hw.c b/audio/audio_hw.c
index 4f6a652..d145b42 100644
--- a/audio/audio_hw.c
+++ b/audio/audio_hw.c
@@ -849,7 +849,7 @@
 static int adev_set_voice_volume(struct audio_hw_device *dev, float volume)
 {
     ALOGV("adev_set_voice_volume: %f", volume);
-    return 0;
+    return -ENOSYS;
 }
 
 static int adev_set_master_volume(struct audio_hw_device *dev, float volume)