[fluid_ops] dropout add default value (PaddlePaddle#72220)

* Fix

* Fix

Author: co63oc

paddle/phi/ops/yaml/ops.yaml

@@ -1535,7 +1535,7 @@
   traits : paddle::dialect::ForwardOnlyTrait
 
 - op : dropout
-  args : (Tensor x, Tensor seed_tensor, Scalar p, bool is_test, str mode, int seed, bool fix_seed)
+  args : (Tensor x, Tensor seed_tensor, Scalar p = 0.5f, bool is_test = false, str mode = "downgrade_in_infer", int seed = 0, bool fix_seed = false)
   output : Tensor(out), Tensor(mask)
   infer_meta :
     func : DropoutInferMeta