Use audio_in_acoustics_t consistently

Change-Id: I0a9dd668fb2e57b1c3ece3190588194974b99062
diff --git a/services/audioflinger/AudioPolicyService.h b/services/audioflinger/AudioPolicyService.h
index 9811670..182b5dd 100644
--- a/services/audioflinger/AudioPolicyService.h
+++ b/services/audioflinger/AudioPolicyService.h
@@ -79,7 +79,7 @@
                                     audio_format_t format = AUDIO_FORMAT_DEFAULT,
                                     uint32_t channels = 0,
                                     audio_in_acoustics_t acoustics =
-                                            (audio_in_acoustics_t)0,
+                                            (audio_in_acoustics_t)0 /*AUDIO_IN_ACOUSTICS_NONE*/,
                                     int audioSession = 0);
     virtual status_t startInput(audio_io_handle_t input);
     virtual status_t stopInput(audio_io_handle_t input);