[llvm] [LLVM] Update AArch64 maintainers (PR #120440)

[Sjoerd Meijer via llvm-commits]

sjoerdmeijer wrote:

+1 to what @aemerson wrote.

Don't know how many volunteers we need, but I could volunteer for general AArch64 codegen too.

https://github.com/llvm/llvm-project/pull/120440