[lld] [LLD][ELF][AArch64] Discard .ARM.attributes sections (PR #125838)

[Peter Smith via llvm-commits]

smithp35 wrote:

I'll wait to the end of the UK day to see if @MaskRay has any input. Otherwise I'll land it and fix up any suggestions post-commit (with apologies). 

https://github.com/llvm/llvm-project/pull/125838