ryzen-monitor-ng: Fix build

makeTargets is not used by the default builder, and was not
calling the necessary make targets.

Added `make clean` to `preBuild` to ensure old files are removed
before building.

pkgs/by-name/ry/ryzen-monitor-ng/package.nix

@@ -14,13 +14,14 @@ stdenv.mkDerivation {
     hash = "sha256-fcW2fEsCFliRnMFnboR0jchzVIlCYbr2AE6AS06cb6o=";
   };
 
-  ## Remove binaries committed into upstream repo
+  # Upstream repo contains pre-compiled binaries and object files
+  # that are out of date.
+  # These need to be removed before build stage.
   preBuild = ''
     rm src/ryzen_monitor
+    make clean
   '';
 
-  makeTargets = [ "clean" "install" ];
-
   installPhase = ''
     runHook preInstall