Intel IOMMU Suspend/Resume Support - Interrupt Remapping

This patch enables suspend/resume for interrupt remapping. During suspend,
interrupt remapping is disabled. When resume, interrupt remapping is enabled
again.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>