[clang] [llvm] Add support for Arm Cortex A78AE CPU (PR #84485)

[Sjoerd Meijer via cfe-commits]

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

Thanks for the quick fix. 
This looks okay to me. But let's see if @DavidSpickett has more comments before merging this. 

https://github.com/llvm/llvm-project/pull/84485