Enable powermanagement, set default cpu governor.

nodes/hosts/nixy/system/bootloader.nix

@@ -49,6 +49,9 @@
     };
   };
 
-  powerManagement.cpuFreqGovernor = "ondemand";
+  powerManagement = {
+    cpuFreqGovernor = "ondemand";
+    enable = "true";
+  };
 }