llvm_10: disable libpfm on aarch32
llvm_10: disable libpfm on aarch32

This is a speculative fix since the llvm_10 build runs OOM currently but it
should also be affected.

See parent commit for more info.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs