[Bugfix] Fix num_hidden_layers when Qwen2-Audio 7B (#1803)

### What this PR does / why we need it?
Fix num_hidden_layers when Qwen2-Audio 7B and #1760 ：
```
INFO 07-15 04:38:53 [platform.py:174] PIECEWISE compilation enabled on NPU. use_inductor not supported - using only ACL Graph mode
Traceback (most recent call last):
  File "/workspace/test1.py", line 58, in <module>
    main(audio_count)
  File "/workspace/test1.py", line 38, in main
    llm = LLM(model="Qwen/Qwen2-Audio-7B-Instruct",
  File "/vllm-workspace/vllm/vllm/entrypoints/llm.py", line 271, in __init__
    self.llm_engine = LLMEngine.from_engine_args(
  File "/vllm-workspace/vllm/vllm/engine/llm_engine.py", line 494, in from_engine_args
    vllm_config = engine_args.create_engine_config(usage_context)
  File "/vllm-workspace/vllm/vllm/engine/arg_utils.py", line 1286, in create_engine_config
    config = VllmConfig(
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/pydantic/_internal/_dataclasses.py", line 123, in __init__
    s.__pydantic_validator__.validate_python(ArgsKwargs(args, kwargs), self_instance=s)
  File "/vllm-workspace/vllm/vllm/config.py", line 4624, in __post_init__
    current_platform.check_and_update_config(self)
  File "/vllm-workspace/vllm-ascend/vllm_ascend/platform.py", line 180, in check_and_update_config
    update_aclgraph_sizes(vllm_config)
  File "/vllm-workspace/vllm-ascend/vllm_ascend/utils.py", line 307, in update_aclgraph_sizes
    num_hidden_layers = vllm_config.model_config.hf_config.num_hidden_layers
  File "/usr/local/python3.10.17/lib/python3.10/site-packages/transformers/configuration_utils.py", line 211, in __getattribute__
    return super().__getattribute__(key)
AttributeError: 'Qwen2AudioConfig' object has no attribute 'num_hidden_layers'
```

### Does this PR introduce _any_ user-facing change?

### How was this patch tested?

Closes: https://github.com/vllm-project/vllm-ascend/issues/1780
https://github.com/vllm-project/vllm-ascend/issues/1760
https://github.com/vllm-project/vllm-ascend/issues/1276
https://github.com/vllm-project/vllm-ascend/issues/359

- vLLM version: v0.10.0
- vLLM main:
7728dd77bb

Signed-off-by: hfadzxy <starmoon_zhang@163.com>

tests/ut/test_utils.py

@@ -260,6 +260,61 @@ class TestUtils(TestBase):
         hits = utils.vllm_version_is.cache_info().hits
         self.assertEqual(hits, 1)
 
+    def test_get_max_hidden_layers(self):
+        from transformers import PretrainedConfig
+
+        class SimpleConfig(PretrainedConfig):
+
+            def __init__(self, num_hidden_layers=12):
+                self.num_hidden_layers = num_hidden_layers
+
+            def to_dict(self):
+                return {"num_hidden_layers": self.num_hidden_layers}
+
+        self.assertEqual(utils.get_max_hidden_layers(SimpleConfig()), 12)
+        self.assertEqual(utils.get_max_hidden_layers(SimpleConfig(24)), 24)
+
+        class NestedConfig(PretrainedConfig):
+
+            def to_dict(self):
+                return {
+                    "model": {
+                        "encoder": {
+                            "num_hidden_layers": 8
+                        },
+                        "decoder": {
+                            "num_hidden_layers": 12
+                        }
+                    },
+                    "other_setting": True
+                }
+
+        self.assertEqual(utils.get_max_hidden_layers(NestedConfig()), 12)
+
+        class MultiValueConfig(PretrainedConfig):
+
+            def to_dict(self):
+                return {
+                    "num_hidden_layers": 6,
+                    "submodule": {
+                        "num_hidden_layers": 18,
+                        "subsub": {
+                            "num_hidden_layers": 9
+                        }
+                    }
+                }
+
+        self.assertEqual(utils.get_max_hidden_layers(MultiValueConfig()), 18)
+
+        class NoLayerConfig(PretrainedConfig):
+
+            def to_dict(self):
+                return {"attention_heads": 8}
+
+        with self.assertRaises(ValueError) as context:
+            utils.get_max_hidden_layers(NoLayerConfig())
+        self.assertIn("num_hidden_layers", str(context.exception))
+
     def test_update_aclgraph_sizes(self):
         # max_num_batch_sizes < len(original_sizes)
         test_compilation_config = CompilationConfig(