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.cpp b/services/audioflinger/AudioFlinger.cpp
index 37f15e2..f94ab84 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -5356,7 +5356,7 @@
                                 audio_format_t *pFormat,
                                 uint32_t *pChannels,
                                 uint32_t *pLatencyMs,
-                                uint32_t flags)
+                                audio_policy_output_flags_t flags)
 {
     status_t status;
     PlaybackThread *thread = NULL;