fix log print of bprop loading

mindspore/ccsrc/ir/primitive.cc

@@ -52,9 +52,6 @@ py::function PrimitivePy::GetBpropFunction() {
     return fn;
   } else {
     auto fn = GetBpropFunctionByObj(python_obj_);
-    if (fn.is_none()) {
-      MS_LOG(WARNING) << "Can't find bprop function for " << name();
-    }
     return fn;
   }
 }

mindspore/ccsrc/utils/primitive_utils.cc

@@ -29,9 +29,6 @@ py::function GetBpropFunctionByObj(py::object obj) {
 
 py::function GetBpropFunction(std::string name) {
   auto fn = GetBpropFunctionByObj(py::str(name));
-  if (fn.is_none()) {
-    MS_LOG(WARNING) << "Can't find bprop function for " << name;
-  }
   return fn;
 }