#1594 --gpu flag in setup.py only enumerates Nvidia GPUs

Descripción

Noticed trying to isolate Strata to a single card in a multi-AMD GPU setup that the arg --gpu only targets Nvidia GPUs and Strata will crash and fail if specified with no Nvidia GPU is present.

The documentation at AMD_HIP.md specifically references this flag as working with AMD cards. From my testing, it does not.

On a side note, specifying a "gpu" key in a strata config.json does work. This allows for full hardware monitoring in the web UI.
HIP_VISIBLE_DEVICES and ROCR_VISIBLE_DEVICES also isolate the device but I found it results in broken GPU monitoring. I am guessing it is caused by an index mismatch between ROCm and the kernel. Therefore my current recommended single-GPU isolation method is via a model config.json.