wined3d: Return the correct parent in IWineD3DVertexDeclarationImpl_GetParent.

dlls/wined3d/vertexdeclaration.c

@@ -432,7 +432,7 @@ ULONG WINAPI IWineD3DVertexDeclarationImpl_Release(IWineD3DVertexDeclaration *if
 HRESULT WINAPI IWineD3DVertexDeclarationImpl_GetParent(IWineD3DVertexDeclaration *iface, IUnknown** parent){
     IWineD3DVertexDeclarationImpl *This = (IWineD3DVertexDeclarationImpl *)iface;
 
-    *parent= (IUnknown*) parent;
+    *parent= This->parent;
     IUnknown_AddRef(*parent);
     TRACE("(%p) : returning %p\n", This, *parent);
     return D3D_OK;