[llvm] [llvm-readobj][offload] Fix llvm-readobj --all on MachO (PR #175912)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

I'm torn on whether or not `--all` should imply offloading, as it's not truly part of the object. At a minimum we should just ignore this if it's MachO. Theoretically you could get this to work there, we'd just need someone to decide on a section name and correctly emit the linker magic that lets us iterate the linked & merged section. But there's really not any motivation to do so as I don't think there's a single person doing or caring about GPU compute on Apple systems.

https://github.com/llvm/llvm-project/pull/175912