fix output of BiasAddGrad.

mindspore/ops/operations/_grad_ops.py

@@ -232,6 +232,8 @@ class BiasAddGrad(PrimitiveWithInfer):
         self.format = validator.check_string(data_format, ['NCHW', 'NHWC', 'NCDHW'], 'format', self.name)
         if context.get_context("device_target") != "GPU" and self.format == "NHWC":
             raise ValueError("NHWC format only support in GPU target.")
+        if self.format == "NCDHW":
+            self.format = "NCHW"
         self.add_prim_attr('data_format', self.format)
 
     def infer_shape(self, d_output):