[llvm] [AArch64][llvm] (NFC) Refactor `sve_intx_dot` class and delete `sve2p1_two_way_dot_vv` (PR #160103)

[Jonathan Thackray via llvm-commits]

jthackray wrote:

> Since we are already merging these 2, we might as well merge both multiclasses together

Thanks, good idea. I tried this, and it looks nice. However, they require different predicates (`HasSVE2p1_or_SME2` and `HasSVE_or_SME`) which precludes joining them easily. So I think I'll have to skip your suggestion.

https://github.com/llvm/llvm-project/pull/160103