[llvm-branch-commits] [llvm] [AArch64][llvm] Fix encoding for `stshh` instruction (#189588) (PR #189679)

[Jonathan Thackray via llvm-branch-commits]

https://github.com/jthackray commented:

This is a cherry-pick (with minor edits) of https://github.com/llvm/llvm-project/pull/189588

https://github.com/llvm/llvm-project/pull/189679