[llvm] [NVPTX] Basic support for fp128 as a storage type (PR #136006)

[Alex MacLean via llvm-commits]

AlexMaclean wrote:

@kazutakahirata, thanks for the quick fix! I'll use `[[maybe_unused]]` and address another oversight on my part in https://github.com/llvm/llvm-project/pull/136207

https://github.com/llvm/llvm-project/pull/136006