[llvm] [AArch64] Fix predicates for SME2p2. (PR #145315)

[Paul Walker via llvm-commits]

paulwalker-arm wrote:

Just to add some colour, you'll see from my fixes that your PR is going in the opposite direction.  Specially, I think the current implementation of HasSVE2p2_or_SME2p2 is correct in that +sve,+sme2p2 should enable the relevant SVE instructions when in non-streaming mode.

https://github.com/llvm/llvm-project/pull/145315