Move control block mName to createTrack() output

This is part of a series of CLs to clean up the shared memory
control block, by removing any fields that don't have to be there.

Change-Id: I6e51003a1293b6800258c31b22cff2eba42162e7
diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h
index da13a7f..523bd32 100644
--- a/include/media/AudioTrack.h
+++ b/include/media/AudioTrack.h
@@ -726,6 +726,7 @@
     sp<AudioTrackClientProxy>       mProxy;         // primary owner of the memory
 
     bool                    mInUnderrun;            // whether track is currently in underrun state
+    String8                 mName;                  // server's name for this IAudioTrack
 
 private:
     class DeathNotifier : public IBinder::DeathRecipient {