style: separate base class members

Author: voltjia

src/base/multi_margin_loss_backward_grad_input.h

@@ -31,17 +31,29 @@ class MultiMarginLossBackwardGradInput
 
  protected:
   Tensor::Shape grad_output_shape_;
+
   Tensor::Strides grad_output_strides_;
+
   DataType grad_output_type_;
+
   Tensor::Shape self_shape_;
+
   Tensor::Strides self_strides_;
+
   DataType self_type_;
+
   Tensor::Shape target_shape_;
+
   Tensor::Strides target_strides_;
+
   DataType target_type_;
+
   Tensor::Shape grad_input_shape_;
+
   Tensor::Strides grad_input_strides_;
+
   DataType grad_input_type_;
+
   int device_index_{0};
 };