x86/efi: Delete dead code when checking for non-native

Both efi_free_boot_services() and efi_enter_virtual_mode() are invoked
from init/main.c, but only if the EFI runtime services are available.
This is not the case for non-native boots, e.g. where a 64-bit kernel is
booted with 32-bit EFI firmware.

Delete the dead code.

Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>