[Bugfix]fix pcp dcp attn aclgraph (#4066)

### What this PR does / why we need it?
In the DCP-PCP graph mode scenario, there is a shape issue with multiple
batches. This PR fixes this problem.

- vLLM version: v0.11.0
- vLLM main:
83f478bb19

---------

Signed-off-by: weiguihua2 <weiguihua2@huawei.com>

vllm_ascend/compilation/acl_graph.py

@@ -7,6 +7,7 @@ from dataclasses import dataclass
 from typing import Any, Callable, Optional
 from unittest.mock import patch
 
+import numpy as np
 import torch
 import torch_npu
 import vllm.envs as envs
@@ -326,9 +327,12 @@ def update_attn_dcp_pcp_params(update_stream, forward_context, runtime_shape):
             actual_seq_lengths_kv = attn_metadata.decode_meta.num_computed_tokens_of_pcp_dcp[:,
                                                                                              pcp_rank,
                                                                                              dcp_rank]
-            if (runtime_shape - len(actual_seq_lengths_kv)) > 0:
-                actual_seq_lengths_kv = actual_seq_lengths_kv + [0] * (
-                    runtime_shape - len(actual_seq_lengths_kv))
+            pad_length = runtime_shape - len(actual_seq_lengths_kv)
+            if pad_length > 0:
+                pad_tensor = np.zeros(pad_length,
+                                      dtype=actual_seq_lengths_kv.dtype)
+                actual_seq_lengths_kv = np.concatenate(
+                    [actual_seq_lengths_kv, pad_tensor])
 
             actual_seq_lengths_q = attn_metadata.actual_seq_lengths_q[:
                                                                       attn_metadata