update TensorFlow test method

TensorFlow/Accuracy_Validation/README.md

@@ -13,7 +13,7 @@
 
 ## 运行
     export HIP_VISIBLE_DEVICES=0    
-    python3 ./benchmarks-master/scripts/tf_cnn_benchmarks/tf_cnn_benchmarks.py --data_format=NCHW --batch_size=128 --model=resnet50 --optimizer=momentum --variable_update=parameter_server  --print_training_accuracy=true  --nodistortions --num_gpus=4 --num_epochs=90 --weight_decay=1e-4 --data_dir=$data_dir_path   --use_fp16=True --data_name=imagenet --train_dir=$save_checkpoint_path
+    python3 ./benchmarks-master/scripts/tf_cnn_benchmarks/tf_cnn_benchmarks.py --data_format=NCHW --batch_size=128 --model=resnet50 --optimizer=momentum --variable_update=parameter_server  --print_training_accuracy=true  --nodistortions --num_gpus=1 --num_epochs=90 --weight_decay=1e-4 --data_dir=$data_dir_path   --use_fp16=True --data_name=imagenet --train_dir=$save_checkpoint_path
 
 # 多卡测试 (单精度)