[llvm] [NVPTX] pass correct GPU arch to ptxas test (PR #81535)

[Joseph Huber via llvm-commits]

https://github.com/jhuber6 approved this pull request.

Seems I might not have these tests run locally despite having CUDA installed. Anything special you need to enable it?

https://github.com/llvm/llvm-project/pull/81535