[llvm] [AArch64][SelectionDAG] Add CodeGen support for scalar FEAT_CPA (PR #105669)

[Alexander Richardson via llvm-commits]

https://github.com/arichardson commented:

I think this looks mostly good now - I will work on submitting some changes shortly so that the "Inverted flag" is not needed anymore.

https://github.com/llvm/llvm-project/pull/105669