This is a first pass at getting the secureboot patches working with the
upstream lockdown patches that got merged. The final patch from our
lockdown set is the sysrq patch which also needs work. For the present
it is not applied.
Use the latest version of the kernel lockdown patch set. This includes a
few configuration renames:
CONFIG_KEXEC_VERIFY_SIG became CONFIG_KEXEC_SIG and
CONFIG_KEXEC_SIG_FORCE was added. CONFIG_KEXEC_SIG_FORCE=n because the
"kexec_file: Restrict at runtime if the kernel is locked down" patch
enforces the signature requirement when the kernel is locked down.
CONFIG_LOCK_DOWN_MANDATORY got renamed to CONFIG_LOCK_DOWN_KERNEL_FORCE
and remains false as LOCK_DOWN_IN_EFI_SECURE_BOOT covers enabling it for
EFI Secure Boot users.
Finally, the SysRq patches got dropped for the present.
