[llvm] [M68k] Add remaining addressing modes for Atomic operations (PR #115523)

[John Paul Adrian Glaubitz via llvm-commits]

glaubitz wrote:

Hmm, building a bootstrap compiler with the patch didn't help.

I had this problem in the past when adding support for 32-bit SPARC to the `object` crate, but I absolutely cannot remember how I fixed it.

https://github.com/llvm/llvm-project/pull/115523