amd-iommu: disable IOMMU hardware on shutdown

When the IOMMU stays enabled the BIOS may not be able to finish the
machine shutdown properly. So disable the hardware on shutdown.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

arch/x86/kernel/pci-dma.c

@@ -290,6 +290,8 @@ static int __init pci_iommu_init(void)
 void pci_iommu_shutdown(void)
 {
 	gart_iommu_shutdown();
+
+	amd_iommu_shutdown();
 }
 /* Must execute after PCI subsystem */
 fs_initcall(pci_iommu_init);