[Chore] Clean up pytorch helper functions in vllm.utils (#26908)

Signed-off-by: Isotr0py <mozf@mail2.sysu.edu.cn>
Signed-off-by: isotr0py <2037008807@qq.com>

vllm/v1/kv_cache_interface.py

@@ -10,7 +10,8 @@ from typing_extensions import Self
 
 from vllm.config import VllmConfig
 from vllm.logger import init_logger
-from vllm.utils import cdiv, get_dtype_size
+from vllm.utils import cdiv
+from vllm.utils.torch_utils import get_dtype_size
 
 logger = init_logger(__name__)