[llvm] [AArch64] Consider [u/s]itofp SVE packing costs (PR #225352)

[Sander de Smalen via llvm-commits]

================

----------------
sdesmalen-arm wrote:

There entries missing for cases where the destination type is larger than the input type, (and vice-versa for the UINT_TO_FP case above, where the source type is larger than the destination type), which I expect also require unpacks/uzps?

https://github.com/llvm/llvm-project/pull/225352