Fix grub_machine_fini bitrot.

Reported by: Glenn Washburn.

grub-core/kern/arm/efi/init.c

@@ -57,10 +57,13 @@ grub_machine_init (void)
 }
 
 void
-grub_machine_fini (void)
+grub_machine_fini (int flags)
 {
   grub_efi_boot_services_t *b;
 
+  if (!(flags & GRUB_LOADER_FLAG_NORETURN))
+    return;
+
   b = grub_efi_system_table->boot_services;
 
   efi_call_3 (b->set_timer, tmr_evt, GRUB_EFI_TIMER_PERIODIC, 0);