Use audio_stream_type_t consistently

At native level it was a mixture of audio_stream_type_t, int, uint32_t,
and uint8_t.  Java is still int.  Also fixed a couple of hard-coded -1
instead of AUDIO_STREAM_DEFAULT, and in startToneCommand a hard-coded 0
instead of AUDIO_STREAM_VOICE_CALL.

Change-Id: Ia33bfd70edca8c2daec9052984b369cd8eee2a83
diff --git a/media/libmediaplayerservice/MidiFile.h b/media/libmediaplayerservice/MidiFile.h
index 2a0dcf9..dfe4318 100644
--- a/media/libmediaplayerservice/MidiFile.h
+++ b/media/libmediaplayerservice/MidiFile.h
@@ -78,7 +78,7 @@
     EAS_I32             mDuration;
     EAS_STATE           mState;
     EAS_FILE            mFileLocator;
-    int                 mStreamType;
+    audio_stream_type_t mStreamType;
     bool                mLoop;
     volatile bool       mExit;
     bool                mPaused;