[llvm] [FIX] Fix sanitizer-aarch64-linux build after commit 8472eb1361bbabd6… (PR #148206)

[Sergey Shcherbinin via llvm-commits]

SergeyShch01 wrote:

@john-brawn-arm, I missed the unused variable in my prev commit ([AArch64LoadStoreOpt] BaseReg update is searched also in CF successor) - could you please approve/merge the fix?

https://github.com/llvm/llvm-project/pull/148206