- emit mlkddn for LRN only for normalizing acorss/within channel (#4074)

*  - emit mlkddn for LRN only for normalizing acorss/within channel

* - remove explicit checking of axes in lrn builder
Co-authored-by: Jayaram Bobba <jayaram.bobba@intel.com>

src/ngraph/runtime/cpu/builder/lrn.cpp

@@ -42,7 +42,7 @@ namespace ngraph
 
                 AxisSet axes = lrn->get_reduction_axes();
 
-                if (runtime::cpu::mkldnn_utils::use_mkldnn_kernel(node) && axes == AxisSet{1})
+                if (runtime::cpu::mkldnn_utils::use_mkldnn_kernel(node))
                 {
                     auto& mkldnn_emitter = external_function->get_mkldnn_emitter();
                     auto lrn_desc = mkldnn_emitter->get_lrn_forward_desc(node);

src/ngraph/runtime/cpu/pass/cpu_assignment.cpp

@@ -548,11 +548,14 @@ namespace ngraph
                 void CPUAssignment::ASSIGN_DECL(ngraph::op::LRN)
                 {
                     (void)external_function;
+                    auto lrn = static_cast<ngraph::op::LRN*>(node);
+                    AxisSet axes = lrn->get_reduction_axes();
                     auto arg0_shape = node->get_input_shape(0);
                     auto arg0_rank = arg0_shape.size();
                     auto result_shape = node->get_output_shape(0);
 
-                    if ((arg0_rank == 4) && node->get_input_element_type(0) == element::f32)
+                    if ((arg0_rank == 4) && node->get_input_element_type(0) == element::f32 &&
+                        axes == AxisSet{1})
                     {
                         runtime::cpu::mkldnn_utils::assign_mkldnn_kernel(node);
                     }