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

[Joseph Huber via cfe-commits]

jhuber6 wrote:

Changing the structure of the ROCm device libraries would be a much more significant undertaking, it wouldn't happen in this PR. Could you say what the issue is exactly again? My understanding is that the python method is finding the incorrect library somehow. This PR's behavior is confusing to me because it seems to defy what `ROCM_PATH` is intended to do, which is to override the search path, into just a "suggestion".

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