[Refactor] Refactor import utils (#20269)

Signed-off-by: yewentao256 <zhyanwentao@126.com>

tools/check_pickle_imports.py

@@ -26,7 +26,6 @@ except ImportError:
 #  add to this list if absolutely necessary and after careful security review.
 ALLOWED_FILES = set([
     # pickle
-    'vllm/utils.py',
     'vllm/v1/serial_utils.py',
     'vllm/v1/executor/multiproc_executor.py',
     'vllm/multimodal/hasher.py',
@@ -54,7 +53,7 @@ ALLOWED_FILES = set([
     'vllm/entrypoints/llm.py',
     'tests/utils.py',
     # pickle and cloudpickle
-    'vllm/utils.py',
+    'vllm/utils/__init__.py',
     'vllm/v1/serial_utils.py',
     'vllm/v1/executor/multiproc_executor.py',
     'vllm/transformers_utils/config.py',