remove cuda env

Signed-off-by: wangli <wangli858794774@gmail.com>

Author: Potabk

vllm_ascend/device_allocator/camem.py

@@ -144,7 +144,7 @@ def get_instance() -> "CaMemAllocator":
         return CaMemAllocator.instance
 
     def __init__(self):
-        conf = os.environ.get("PYTORCH_CUDA_ALLOC_CONF", "")
+        conf = os.environ.get("PYTORCH_NPU_ALLOC_CONF", "")
         assert "expandable_segments:True" not in conf, \
             ("Expandable segments are not compatible with memory pool. "
             "Please track https://github.com/pytorch/pytorch/issues/147851 "