!4122 fix bug in bert script

Merge pull request !4122 from yoonlee666/master_bug

model_zoo/official/nlp/bert/src/utils.py

@@ -20,6 +20,7 @@ Functional Cells used in Bert finetune and evaluation.
 import os
 import numpy as np
 import mindspore.nn as nn
+from mindspore import log as logger
 from mindspore.ops import operations as P
 from mindspore.common.tensor import Tensor
 from mindspore.common import dtype as mstype