Remove unneeded NULL casts.

diff --git a/dlls/dmscript/scripttrack.c b/dlls/dmscript/scripttrack.c
index bbea145..31865ea 100644
--- a/dlls/dmscript/scripttrack.c
+++ b/dlls/dmscript/scripttrack.c
@@ -259,7 +259,7 @@
 	
 	track = HeapAlloc (GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(IDirectMusicScriptTrack));
 	if (NULL == track) {
-		*ppobj = (LPVOID) NULL;
+		*ppobj = NULL;
 		return E_OUTOFMEMORY;
 	}
 	track->UnknownVtbl = &DirectMusicScriptTrack_Unknown_Vtbl;