elfutils: always depend on pkg-config

This elfutils commit:
https://github.com/roolebo/elfutils/commit/30b5592a34a69b43018763428a0bfbe29d91ab68
moved the pkg-config check to the top level, causing the build to fail
with debuginfod disabled. Fix it by making our pkg-config depdendency
unconditional.

pkgs/by-name/el/elfutils/package.nix

@@ -87,8 +87,8 @@ stdenv.mkDerivation (finalAttrs: {
     flex
     gettext
     bzip2
-  ]
-  ++ lib.optional enableDebuginfod pkg-config;
+    pkg-config
+  ];
   buildInputs = [
     zlib
     zstd