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

[via cfe-commits]

b-sumner 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

It depends on the device and the system.  In this case, since linux provides an alternative I agree it makes sense to use it, and now see why this is not a workaround.  Thanks.

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