fix composite mean op map

paddle/phi/api/yaml/op_compat.yaml

@@ -1138,8 +1138,14 @@
   extra :
     attrs : [bool use_mkldnn = false]
 
-- op : reduce_mean
+- op : mean (reduce_mean)
   backward : reduce_mean_grad
+  inputs :
+    x : X
+  outputs :
+    out : Out
+  attrs :
+    {axis : dim, keepdim : keep_dim}
   extra :
     attrs : [bool use_mkldnn = false]
 

python/paddle/incubate/autograd/utils.py

@@ -183,6 +183,7 @@ def _get_args_values(op, phi_name):
                 and arg_name in op_content["attrs"].keys()
             ):
                 attrs.append(op.attr(op_content["attrs"][arg_name]))
+            else:
                 attrs.append(op.attr(arg_name))
 
     return inputs, attrs