[clang] [AArch64][SME] Fix bug on SMELd1St1 (PR #118109)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

> I thought that this fix will automatically pull from main to other branch at some tiime

main is the basis for all future release branches (20.x and later), but we don't automatically pull fixes into release branches that are already created (19.x).

See https://llvm.org/docs/GitHub.html#backporting-fixes-to-the-release-branches for backporting instructions.

https://github.com/llvm/llvm-project/pull/118109