[llvm] [llvm][AArch64] Support -mcpu=apple-m4 (PR #95478)

[Jon Roelofs via llvm-commits]

jroelofs wrote:

> @jroelofs So does the actual spec define 9.0 as requiring SVE, or just LLVM? if just llvm, can we fix this within llvm?

As I explained in the comment, it is just an llvm quirk, and not the Arm ARM that requires this. Fixing it might be painful. Depends on how many projects are incorrectly assuming v9.0 implies SVE support at this point.

https://github.com/llvm/llvm-project/pull/95478