[llvm] [NVPTX][NFC] Use preferred LLVM coding style in NVPTX backend (PR #190572)

[Alex MacLean via llvm-commits]

AlexMaclean wrote:

I think the description is far too verbose for this change. Please rewrite with something shorter and keep in mind the [LLVM AI Tool Use Policy](https://llvm.org/docs/AIToolPolicy.html#details) strongly recommended that contributors write PR descriptions themselves (as opposed to using AI). 

https://github.com/llvm/llvm-project/pull/190572