m_direct_execution is used but not defined when NGRAPH_DEX_ONLY=TRUE (#1910)

* m_direct_execution is used but not defined when NGRAPH_DEX_ONLY=TRUE

* keep the ifdef and move m_direct_execution out of the ifdef

src/ngraph/runtime/cpu/cpu_external_function.hpp

@@ -230,8 +230,8 @@ namespace ngraph
                 bool m_use_tbb;
 #if !defined(NGRAPH_DEX_ONLY)
                 bool m_is_compiled;
-                bool m_direct_execution;
 #endif
+                bool m_direct_execution;
                 EntryPoint m_compiled_function;
                 std::unordered_map<std::string, std::string> m_variable_name_map;