x86: Don't put iommu_shutdown_noop() in init section

It causes kernel panic on shutdown or reboot.
Signed-off-by: NHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
LKML-Reference: <4B00BC8E.50801@ct.jp.nec.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/x86_init.c

@@ -20,7 +20,7 @@ void __cpuinit x86_init_noop(void) { }
 void __init x86_init_uint_noop(unsigned int unused) { }
 void __init x86_init_pgd_noop(pgd_t *unused) { }
 int __init iommu_init_noop(void) { return 0; }
-void __init iommu_shutdown_noop(void) { }
+void iommu_shutdown_noop(void) { }
 
 /*
  * The platform setup functions are preset with the default functions