[llvm] [Offload] `olEnqueueHostCallback` (PR #152482)

[Joseph Huber via llvm-commits]

https://github.com/jhuber6 commented:

This function is basically launching a kernel expect it runs on the host. We have `olLaunchKernel` so maybe `olLaunchFunction` or `olLaunchHostFunc`?

https://github.com/llvm/llvm-project/pull/152482