fix init file

python/paddle/nn/functional/__init__.py

@@ -193,3 +193,4 @@ from .vision import shuffle_channel  #DEFINE_ALIAS
 from .vision import space_to_depth  #DEFINE_ALIAS
 from .vision import yolo_box  #DEFINE_ALIAS
 from .vision import yolov3_loss  #DEFINE_ALIAS
+from .input import one_hot  #DEFINE_ALIAS