Use NULL not 0 for raw pointers

Use if (p != NULL) instead of if (ptr)

Change-Id: Iaec3413a59ccbf233c98fcd918cc7d70ac5da9fa
diff --git a/media/libmedia/IAudioFlingerClient.cpp b/media/libmedia/IAudioFlingerClient.cpp
index 5a3f250..9458bc0 100644
--- a/media/libmedia/IAudioFlingerClient.cpp
+++ b/media/libmedia/IAudioFlingerClient.cpp
@@ -73,7 +73,7 @@
             CHECK_INTERFACE(IAudioFlingerClient, data, reply);
             int event = data.readInt32();
             int ioHandle = data.readInt32();
-            void *param2 = 0;
+            void *param2 = NULL;
             AudioSystem::OutputDescriptor desc;
             uint32_t stream;
             if (event == AudioSystem::STREAM_CONFIG_CHANGED) {