message: [Intel MKL] Fixing Device() API usage in mkl_eager_op_rewrite.cc
  API change in TF core caused a build failure in MKL CPU backend. This commit fixes the compilation failure.
diff: @@ -135,11 +135,13 @@ Status MklEagerOpRewrite::SetupNewOp(
  ->MutableAttrs()
  ->Set("_kernel", mkl_op_registry::kMklNameChangeOpLabel);
  - if (orig_op->Device() != nullptr) {
  - (*new_mkl_op)->SetDevice(orig_op->Device());
  - } else {
  + if (orig_op->Device() == kVariantDeviceNull) {
  string device_name = orig_op->GetDeviceName();
  (*new_mkl_op)->SetDeviceName(device_name.c_str());
  + } else if (VariantDeviceIsCustom(orig_op->Device())) {
  + (*new_mkl_op)->SetDevice(absl::get<CustomDevice*>(orig_op->Device()));
  + } else {
  + (*new_mkl_op)->SetDevice(absl::get<Device*>(orig_op->Device()));
  }
  return Status::OK();
  }
  