Update comments

Change-Id: I327663a020670d0a72ff57bd0b682e2ce0528650
diff --git a/media/libmediaplayerservice/MediaPlayerService.cpp b/media/libmediaplayerservice/MediaPlayerService.cpp
index 8f62ee4..148018d 100644
--- a/media/libmediaplayerservice/MediaPlayerService.cpp
+++ b/media/libmediaplayerservice/MediaPlayerService.cpp
@@ -1571,7 +1571,7 @@
                 AUDIO_POLICY_OUTPUT_FLAG_NONE,
                 CallbackWrapper,
                 mCallbackData,
-                0,
+                0,  // notification frames
                 mSessionId);
     } else {
         t = new AudioTrack(