[clang] [amdgpu-arch] Replace use of HSA with reading sysfs directly (PR #116651)

[Matt Arsenault via cfe-commits]

arsenm wrote:

We shouldn't need to load a driver to query the devices on the system. This exists for this purpose, if there isn't going to be some ioctl to read it for you 

https://github.com/llvm/llvm-project/pull/116651