Use 0 for sp<>, NULL for raw pointers

Change-Id: Ia0595afdc41e1dec428d7a3db73558b54c417bf3
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 2c2931f..fcdea91 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -1248,7 +1248,7 @@
             track = TimedTrack::create(this, client, streamType, sampleRate, format,
                     channelMask, frameCount, sharedBuffer, sessionId);
         }
-        if (track == 0 || track->getCblk() == NULL || track->name() < 0) {
+        if (track == 0 || track->getCblk() == 0 || track->name() < 0) {
             lStatus = NO_MEMORY;
             goto Exit;
         }