[llvm] [AArch64] Add an early return and de-indent a long indented block (NFC) (PR #201345)

[David Green via llvm-commits]

https://github.com/davemgreen approved this pull request.

This sounds OK. My personal preference is generally to keep the code as it was before to help git-blame if there isn't a strong reason to change it, but this looks sensible enough. LGTM

https://github.com/llvm/llvm-project/pull/201345