[llvm] [AMDGPU][Passes] Invoke CGSCCOptimizerLateEP callbacks in LTO pipeline (PR #203262)

[Arthur Eubanks via llvm-commits]

aeubanks wrote:

I don't see why this was omitted by design, seems more like an oversight to me. Why do you say CGSCCOptimizerLateEP is only per-TU, as opposed to the other extension points?

https://github.com/llvm/llvm-project/pull/203262