efi: x86/xen: switch to efi_get_secureboot_mode helper

Now that we have a static inline helper to discover the platform's secure
boot mode that can be shared between the EFI stub and the kernel proper,
switch to it, and drop some comments about keeping them in sync manually.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2 files changed