Fix device return is bytecode instead of str

[CXIAAAAA]

File "/host/vllm/vllm/engine/arg_utils.py", line 1293, in _override_v1_engine_args
if "h100" in device_name or "h200" in device_name:
TypeError: a bytes-like object is required, not 'str'

[github-actions]

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[hmellor]

Should we also ensure that get_device_name() always returns a string? So that we don't have to make this patch anywhere else that it's called?

[mgoin]

I agree with @hmellor as this is the same root issue as #12565

[DarkLight1337]

cc @youkaichao

This is caused by old version of pynvml. We should improve the error message to notify users to update the library version instead of just printing out a warning message.

[hmellor]

Closing in favour of #12636