[llvm] [AArch64] Ensure the type of LDNP/STNP is always v2i64 (PR #150378)

[David Green via llvm-commits]

davemgreen wrote:

> LGTM, thanks
> 
> Perhaps we could avoid bitcasts by relaxing the type constraint?

I wasn't sure how that would work without having multiple patterns (for each type). Maybe I am missing how it would work though?

https://github.com/llvm/llvm-project/pull/150378