fix ac imagenet demo (PaddlePaddle#1063)

* fix demo

* fix demo

Author: ceci3

demo/auto-compression/README.md

@@ -77,6 +77,7 @@ python demo_imagenet.py \
     --save_dir='./save_qat_mbv2/' \
     --devices='gpu' \
     --batch_size=64 \
+    --data_dir='../data/ILSVRC2012/' \
     --config_path='./configs/CV/mbv2_qat_dis.yaml'
 ```
 
@@ -90,6 +91,7 @@ python demo_imagenet.py \
     --save_dir='./save_qat_mbv2/' \
     --devices='gpu' \
     --batch_size=64 \
+    --data_dir='../data/ILSVRC2012/' \
     --config_path='./configs/CV/mbv2_ptq_hpo.yaml'
 ```
 
@@ -119,5 +121,6 @@ python demo_imagenet.py \
     --save_dir='./save_qat_mbv2/' \
     --devices='gpu' \
     --batch_size=64 \
+    --data_dir='../data/ILSVRC2012/' \
     --config_path='./configs/CV/xxx.yaml'
 ```

demo/auto-compression/demo_imagenet.py

@@ -33,7 +33,7 @@ def reader_wrapper(reader):
     def gen():
         for i, data in enumerate(reader()):
             imgs = np.float32([item[0] for item in data])
-            yield {"inputs": imgs}
+            yield {"x": imgs}
 
     return gen