Use audio_policy_output_flags_t consistently

This affects:
 - IAudioFlinger::openOutput
 - AudioTrack::AudioTrack
 - AudioTrack::set
 - apps that call these

Change-Id: I26fb281bac6cb87593d17697bc9cb37a835af205
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index d9f2972..38fff8c 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -143,7 +143,7 @@
                                     audio_format_t *pFormat,
                                     uint32_t *pChannels,
                                     uint32_t *pLatencyMs,
-                                    uint32_t flags);
+                                    audio_policy_output_flags_t flags);
 
     virtual audio_io_handle_t openDuplicateOutput(audio_io_handle_t output1,
                                                   audio_io_handle_t output2);