A single regression fix for x86:

  Moving the invocation of arch_cpu_finalize_init() earlier in the boot
  process caused a boot regression on IBT enabled system.

  The root cause is not the move of arch_cpu_finalize_init() itself. The
  system fails to boot because the subsequent efi_enter_virtual_mode() code
  has a non-IBT safe EFI call inside. This was never noticed because IBT
  was enabled after the EFI initialization.

  Switching the EFI call to use the IBT safe wrapper cures the problem.