[llvm] [NFC][AArch64] Extract MOVaddr* expansion model into common header (PR #183503)

[David Green via llvm-commits]

https://github.com/davemgreen commented:

I don't have a strong opinion on it, but I was hoping to use this header for things that are imm's but not really pseudos. I dont think I would be against keeping the old name, even if it isnt perfect either way.

https://github.com/llvm/llvm-project/pull/183503