qcap: Remove superfluous pointer casts.

dlls/qcap/capturegraph.c

diff --git a/dlls/qcap/capturegraph.c b/dlls/qcap/capturegraph.c
index b858762..7294d5d 100644
--- a/dlls/qcap/capturegraph.c
+++ b/dlls/qcap/capturegraph.c
@@ -78,9 +78,9 @@
 /*
   converts This to an interface pointer
 */
-#define _IUnknown_(This)                (IUnknown*)&(This->lpVtbl2)
-#define _ICaptureGraphBuilder_(This)    (ICaptureGraphBuilder*)&(This->lpVtbl)
-#define _ICaptureGraphBuilder2_(This)   (ICaptureGraphBuilder2*)&(This->lpVtbl2)
+#define _IUnknown_(This)              (&(This)->lpVtbl2)
+#define _ICaptureGraphBuilder_(This)  (&(This)->lpVtbl)
+#define _ICaptureGraphBuilder2_(This) ((ICaptureGraphBuilder2*)&(This)->lpVtbl2)
 
 
 IUnknown * CALLBACK QCAP_createCaptureGraphBuilder2(IUnknown *pUnkOuter,