Update Generic CPU backend to new Backend API (#2439)

* update gcpu to new backend api

* cleanup

* undo change

src/ngraph/runtime/generic_cpu/CMakeLists.txt

@@ -20,7 +20,7 @@ if (NGRAPH_GENERIC_CPU_ENABLE)
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
     endif()
-    add_library(gcpu_backend SHARED gcpu_backend.cpp node_wrapper.cpp)
+    add_library(gcpu_backend SHARED gcpu_backend.cpp gcpu_executable.cpp node_wrapper.cpp)
     if(NGRAPH_LIB_VERSIONING_ENABLE)
         set_target_properties(gcpu_backend PROPERTIES
             VERSION ${NGRAPH_VERSION}

src/ngraph/runtime/generic_cpu/kernel/broadcast.hpp

@@ -33,7 +33,7 @@ namespace ngraph
         {
             namespace kernel
             {
-                std::tuple<size_t, size_t> get_start_finish(size_t size)
+                static std::tuple<size_t, size_t> get_start_finish(size_t size)
                 {
                     const size_t nthreads = omp_get_num_threads();
                     const size_t ithread = omp_get_thread_num();