Add attribute visitor to Gelu op (#4387)

Co-authored-by: Sang Ik Lee <sang.ik.lee@intel.com>
Co-authored-by: Scott Cyphers <diyessi@users.noreply.github.com>

src/ngraph/op/fused/gelu.cpp

@@ -37,6 +37,11 @@ op::Gelu::Gelu(const Output<Node>& data)
     constructor_validate_and_infer_types();
 }
 
+bool ngraph::op::v0::Gelu::visit_attributes(AttributeVisitor& visitor)
+{
+    return true;
+}
+
 // f(x) = 0.5 * x * (1.0 + erf( x / sqrt(2.0) )
 NodeVector op::Gelu::decompose_op() const
 {

src/ngraph/op/fused/gelu.hpp

@@ -39,6 +39,7 @@ namespace ngraph
                 /// \param data Input tensor
                 Gelu(const Output<Node>& data);
 
+                bool visit_attributes(AttributeVisitor& visitor) override;
                 virtual NodeVector decompose_op() const override;
 
                 void pre_validate_and_infer_types() override;