[clang] [Clang] Rename OffloadArch::UNUSED to UNUSED_ to avoid macro collisions (PR #174528)

[Khem Raj via cfe-commits]

kraj wrote:

> Why is this enum using all-caps names in the first place? It's against coding standard. (https://llvm.org/docs/CodingStandards.html#name-types-functions-variables-and-enumerators-properly)

Good question, although this would need wholesome change, which could be done as a separate commit IMO

https://github.com/llvm/llvm-project/pull/174528