DIN: fix bug in using place (#4386)

PaddleRec/din/infer.py

@@ -80,7 +80,7 @@ def infer():
 
     loader = fluid.io.DataLoader.from_generator(
         feed_list=[inference_program.block(0).var(e) for e in feed_target_names], capacity=10000, iterable=True)
-    loader.set_sample_list_generator(data_reader, places=fluid.cuda_places())
+    loader.set_sample_list_generator(data_reader, places=place)
 
     loss_sum = 0.0
     score = []

PaddleRec/din/train.py

@@ -96,7 +96,7 @@ def train():
 
     loader = fluid.io.DataLoader.from_generator(
         feed_list=feed_list, capacity=10000, iterable=True)
-    loader.set_sample_list_generator(data_reader, places=fluid.cuda_places())
+    loader.set_sample_list_generator(data_reader, places=place)
     if use_parallel:
         train_exe = fluid.ParallelExecutor(
             use_cuda=use_cuda, loss_name=avg_cost.name)