Remove unnecessary wxIsWindowOrParentDisabled()

wxWindow::IsEnabled() already returns false if any of the window
ancestors are disabled, there is no need to check them explicitly.

src/osx/window_osx.cpp

@@ -565,20 +565,9 @@ bool wxWindowMac::SetBackgroundColour(const wxColour& col )
     return true ;
 }
 
-static bool wxIsWindowOrParentDisabled(wxWindow* w)
-{
-    while (w && !w->IsTopLevel())
-    {
-        if (!w->IsEnabled())
-            return true;
-        w = w->GetParent();
-    }
-    return false;
-}
-
 void wxWindowMac::SetFocus()
 {
-    if (wxIsWindowOrParentDisabled((wxWindow*) this))
+    if ( !IsEnabled() )
         return;
 
     wxWindow* former = FindFocus() ;