audio policy: use audio_devices_t when appropriate

Change-Id: I1b3a5879e81c789fb53d356af3d3a1ee2dca955f
diff --git a/services/audioflinger/AudioPolicyService.cpp b/services/audioflinger/AudioPolicyService.cpp
index 753b1d2..62768bf 100644
--- a/services/audioflinger/AudioPolicyService.cpp
+++ b/services/audioflinger/AudioPolicyService.cpp
@@ -432,10 +432,12 @@
     return mpAudioPolicy->get_strategy_for_stream(mpAudioPolicy, stream);
 }
 
-uint32_t AudioPolicyService::getDevicesForStream(audio_stream_type_t stream)
+//audio policy: use audio_device_t appropriately
+
+audio_devices_t AudioPolicyService::getDevicesForStream(audio_stream_type_t stream)
 {
     if (mpAudioPolicy == NULL) {
-        return 0;
+        return (audio_devices_t)0;
     }
     return mpAudioPolicy->get_devices_for_stream(mpAudioPolicy, stream);
 }