[llvm] [llvm][offload] Move AMDGPU offload utilities to LLVM (PR #102487)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> Yes, we have `llvm/Frontend/Offloading/Utility.h`, I can move it there.
> 
> However, I didn't add it there because the files have different purposes, one is almost entirely for offload entries and the other ELF utilities.

That's just the only thing I could think to put there at the time, should be usable for other things.

https://github.com/llvm/llvm-project/pull/102487