d3dx8: Fix a typo in d3dx8math.h.

include/d3dx8math.h

@@ -380,7 +380,7 @@ DECLARE_INTERFACE_(ID3DXMatrixStack, IUnknown)
 #define ID3DXMatrixStack_QueryInterface(p,a,b)            (p)->lpVtbl->QueryInterface(p,a,b)
 #define ID3DXMatrixStack_AddRef(p)                        (p)->lpVtbl->AddRef(p)
 #define ID3DXMatrixStack_Release(p)                       (p)->lpVtbl->Release(p)
-#define ID3DXMAtrixStack_Pop(p)                           (p)->lpVtbl->Pop(p)
+#define ID3DXMatrixStack_Pop(p)                           (p)->lpVtbl->Pop(p)
 #define ID3DXMatrixStack_Push(p)                          (p)->lpVtbl->Push(p)
 #define ID3DXMatrixStack_LoadIdentity(p)                  (p)->lpVtbl->LoadIdentity(p)
 #define ID3DXMatrixStack_LoadMatrix(p,a)                  (p)->lpVtbl->LoadMatrix(p,a)