[llvm] BPF: Ensure __sync_fetch_and_add() always generate atomic_fetch_add insn (PR #101428)

[Peilin Ye via llvm-commits]

peilin-ye wrote:

Thanks for the quick fix!  The reporter's first name in the commit message should be "Peilin".

https://github.com/llvm/llvm-project/pull/101428