add linux_{default,latest} to linuxKernel.kernels (#317498)

       then latest

       else testing;

    linux_default = packageAliases.linux_default.kernel;

    linux_latest = packageAliases.linux_latest.kernel;

    # Using zenKernels like this due lqx&zen came from one source, but may have different base kernel version

    # https://github.com/NixOS/nixpkgs/pull/161773#discussion_r820134708

    zenKernels = callPackage ../os-specific/linux/kernel/zen-kernels.nix;