[llvm] [AArch64] Fix incorrectly getting the destination reg of an insn (PR #101205)

[Momchil Velikov via llvm-commits]

momchil-velikov wrote:

> Should this be backported or does 19.x work as is?

IMHO, no need, the compiler works just fine without this change, albeit by accident, the risk of introducing unrelated changes that would suddenly make *this* change matter, seems low.

https://github.com/llvm/llvm-project/pull/101205