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

[Matthias Gehre via cfe-commits]

mgehre-amd wrote:

> > ROCM_PATH doesn't always have a layout where the device libraries can be found
> 
> Isn't this an issue in the user setup? I thought we have well-defined directory layout?

>From what I understand, this problem (https://github.com/ROCm/TheRock/issues/785) comes up when installing ROCm via the python wheels (like `uv pip install --index-url=https://rocm.nightlies.amd.com/v2-staging/gfx1151 'rocm[devel]'`), where the ROCM_PATH layout seems to be different than when doing the installation from tarball.

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