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.