wxUniv/MSW compilation fix.

wxUniv/MSW compilation was broken by r65589, fix it by not assuming that
wxWindowMSW is a wxWindow because wxWindow derives from it in wxUniv.

Closes #12534.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65804 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/window.cpp

@@ -5648,12 +5648,12 @@ void
 MSWInitAnyKeyEvent(wxKeyEvent& event,
                    WXWPARAM wParam,
                    WXLPARAM lParam,
-                   const wxWindow *win /* may be NULL */)
+                   const wxWindowBase *win /* may be NULL */)
 {
     if ( win )
     {
         event.SetId(win->GetId());
-        event.SetEventObject(const_cast<wxWindow *>(win));
+        event.SetEventObject(const_cast<wxWindowBase *>(win));
     }
     else // No associated window.
     {