Remove unneeded NULL casts.

diff --git a/dlls/dmstyle/style.c b/dlls/dmstyle/style.c
index 2941a63..49b8080 100644
--- a/dlls/dmstyle/style.c
+++ b/dlls/dmstyle/style.c
@@ -1041,7 +1041,7 @@
 	
   obj = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(IDirectMusicStyle8Impl));
   if (NULL == obj) {
-    *ppobj = (LPVOID) NULL;
+    *ppobj = NULL;
     return E_OUTOFMEMORY;
   }
   obj->UnknownVtbl = &DirectMusicStyle8_Unknown_Vtbl;