default to stable kernel

Author: tstat

rpi/default.nix

@@ -14,7 +14,7 @@ in
   options = with lib; {
     raspberry-pi-nix = {
       kernel-version = mkOption {
-        default = "v6_6_67";
+        default = "v6_6_51";
         type = types.str;
         description = "Kernel version to build.";
       };