efi: Lock down the kernel if booted in secure boot mode
    (jsc#SLE-9870, bsc#1198101).
    
    - Update config files.
      - The shim for openSUSE Tumbleweed needs to be reviewed by upstream
        and signed by Microsoft. So we need to lockdown kernel on x86_64
        and arm64 because EFI secure boot.
      - We disable CONFIG_LOCK_DOWN_IN_EFI_SECURE_BOOT in other
        architectures.