[llvm] [AMDGPU] Move `AMDGPUAttributorPass` to full LTO post link stage (PR #102086)

[Johannes Doerfert via llvm-commits]

https://github.com/jdoerfert approved this pull request.

I think the pass is basically mandatory, but I won't argue with it being default on.

https://github.com/llvm/llvm-project/pull/102086