Remove unnecessary parameter

Just get the parameter on server side

Change-Id: I433a63104dbb257e0d862be2ab61847cb36d1c15
diff --git a/media/libmedia/AudioTrack.cpp b/media/libmedia/AudioTrack.cpp
index 1d87ff8..d0872f0 100644
--- a/media/libmedia/AudioTrack.cpp
+++ b/media/libmedia/AudioTrack.cpp
@@ -837,8 +837,7 @@
         }
     }
 
-    sp<IAudioTrack> track = audioFlinger->createTrack(getpid(),
-                                                      streamType,
+    sp<IAudioTrack> track = audioFlinger->createTrack(streamType,
                                                       sampleRate,
                                                       // AudioFlinger only sees 16-bit PCM
                                                       format == AUDIO_FORMAT_PCM_8_BIT ?