[clang] [Clang][HIP] Make device PGO imply offload LTO (PR #225444)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

@arsenm @jhuber6 Thanks, you are right. Normal HIP already uses offload LTO by default. I was looking at the special non-RDC `--offload-device-only` path, which emits an object.

I rechecked the HIPRTC flow. LLD can link that object with the bitcode profile runtime directly, and the full generate, run, merge, and profile-use test passes without forcing offload LTO. So this change is not needed. I will close the PR.

https://github.com/llvm/llvm-project/pull/225444