[clang] [AArch64][SME] Warn when using a streaming builtin from a non-streaming function (PR #75487)

[Nico Weber via cfe-commits]

nico wrote:

If it's not too much trouble, could you `git cherry-pick c60663d128f8e0dccd418bdf16ecc403b96aa74a` into this? (Cool if not, ofc.)

https://github.com/llvm/llvm-project/pull/75487