[clang] AMDGPU: Find device files even when ROCM_PATH is set (PR #177346)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 commented:

These files really should live with the compiler. They should ideally go in `lib/clang/23/lib/amdgcn-amd-amdhsa` so they don't require the ROCm platform to build since they're a language dependency right now.

This seems strange to me, the environment variable is intentionally overriding the rest of the search behavior. Is the intention to just make the environment variable a fallback instead of the only one it will find?

https://github.com/llvm/llvm-project/pull/177346