[llvm] [AArch64][SME] Fix iterator to fixupCalleeSaveRestoreStackOffset (PR #110855)

[via llvm-commits]

llvmbot wrote:

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Failed to cherry-pick: f314e12494ed73290983a7db8e15c21578f437b3

https://github.com/llvm/llvm-project/actions/runs/12018902390

Please manually backport the fix and push it to your github fork.  Once this is done, please create a [pull request](https://github.com/llvm/llvm-project/compare)

https://github.com/llvm/llvm-project/pull/110855