[Eager] fix unpool and yaml config (#45544)

paddle/phi/api/yaml/legacy_backward.yaml

@@ -2715,7 +2715,6 @@
   kernel:
     func: unpool3d_grad
     data_type: x
-  no_need_buffer : x
 
 - backward_api: unpool_grad
   forward: unpool (Tensor x, Tensor indices, int[] ksize, int[] strides, int[] padding,  int[] output_size, str data_format) -> Tensor(out)
@@ -2727,4 +2726,3 @@
   kernel:
     func: unpool_grad
     data_type: x
-  no_need_buffer : x

python/paddle/nn/functional/pooling.py

@@ -878,7 +878,7 @@ def max_unpool2d(x,
     if in_dygraph_mode():
         output = _C_ops.unpool(x, indices, kernel_size, stride, padding,
                                output_size, data_format)
-
+        return output
     elif in_dynamic_mode():
         output = _legacy_C_ops.unpool(x, indices, 'unpooling_type', 'max',
                                       'ksize', kernel_size, 'strides', stride,
@@ -995,6 +995,7 @@ def max_unpool3d(x,
     if in_dygraph_mode():
         output = _C_ops.unpool3d(x, indices, kernel_size, stride, padding,
                                  output_size, data_format)
+        return output
     elif in_dynamic_mode():
         output = _legacy_C_ops.unpool3d(x, indices, 'unpooling_type', 'max',
                                         'ksize', kernel_size, 'strides', stride,