kernel: fix config generation

Addresses https://github.com/NixOS/nixpkgs/issues/71803:
Kernel options are not merged as described, especially the "optional"
aspects. The error silences legitimate warnings.

pkgs/os-specific/linux/kernel/generic.nix

@@ -158,11 +158,8 @@ let
         ;
       }).config;
 
-      #
       structuredConfig = moduleStructuredConfig.settings;
     };
-
-
   }; # end of configfile derivation
 
   kernel = (callPackage ./manual-config.nix {}) {