[clang] clang: Remove BoundArch assert in AMDGPUToolChain::addClangTargetOptions (PR #203060)

[Matt Arsenault via cfe-commits]

arsenm wrote:

> Any clue why Flang uses this instead of the OpenMP or HIP one?

I have no idea why any of the subclasses of AMDGPUToolChain exist. They should all be merged into one. The only special case is the not-offload OpenCL/bitcode which we can check against OFK_None. The offload languages should all behave identically, and the pointless divergence between them is just terrible QoI

https://github.com/llvm/llvm-project/pull/203060