Support platform.get_device_uuid function (#6777)

### What this PR does / why we need it?
Support platform.get_device_uuid function.
currently, the pytorch.npu.get_device_properties return uuid as full
zero, vllm-ascend implement the interface at first, once the
pytorch.npu.get_device_properties return the real uuid, vllm-ascend will
support without modification.
more details see 
https://github.com/vllm-project/vllm-ascend/issues/6669
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?

- vLLM version: v0.15.0
- vLLM main:
9562912cea
root@localhost:/workspace/l00614971/vllm_test# python vllm_test.py 
INFO 02-24 09:43:48 [__init__.py:43] Available plugins for group
vllm.platform_plugins:
INFO 02-24 09:43:48 [__init__.py:45] - ascend -> vllm_ascend:register
INFO 02-24 09:43:48 [__init__.py:48] All plugins in this group will be
loaded. Set `VLLM_PLUGINS` to control which plugins to load.
INFO 02-24 09:43:48 [__init__.py:217] Platform plugin ascend is
activated
device_uuid =  00000000-0000-0000-0000-000000000000

---------

Signed-off-by: liziyu <liziyu16@huawei.com>
Signed-off-by: wangxiaoteng <wangxiaoteng@huawei.com>
Signed-off-by: luomin2005 <luomin2005@huawei.com>
Co-authored-by: liziyu <56102866+liziyu179@users.noreply.github.com>
Co-authored-by: wangxiaoteng <wangxiaoteng@huawei.com>

vllm_ascend/platform.py

@@ -162,6 +162,13 @@ class NPUPlatform(Platform):
     def get_device_name(cls, device_id: int = 0) -> str:
         return torch.npu.get_device_name(device_id)
 
+    @classmethod
+    def get_device_uuid(cls, device_id: int = 0) -> str:
+        device_props = torch.npu.get_device_properties(device_id)
+        if not hasattr(device_props, "uuid") or device_props.uuid is None:
+            raise RuntimeError(f"Device {device_id} does not have a valid UUID.")
+        return device_props.uuid
+
     @classmethod
     def inference_mode(cls):
         return torch.inference_mode()