[mlir] [clang] [llvm] [AArch64] Replace LLVM IR function attributes for PSTATE.ZA. (PR #79166)

[Cullen Rhodes via cfe-commits]

https://github.com/c-rhodes commented:

MLIR changes LGTM cheers, just left one comment for something I missed when the preserved attr was added recently.

Also, in the commit message the LLVM IR attributes are prefixed with `arm`, should be `aarch64`.

https://github.com/llvm/llvm-project/pull/79166