iommu: Introduce new 'struct iommu_device'

This struct represents one hardware iommu in the iommu core
code. For now it only has the iommu-ops associated with it,
but that will be extended soon.

The register/unregister interface is also added, as well as
making use of it in the Intel and AMD IOMMU drivers.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

include/linux/intel-iommu.h

@@ -29,6 +29,7 @@
 #include <linux/dma_remapping.h>
 #include <linux/mmu_notifier.h>
 #include <linux/list.h>
+#include <linux/iommu.h>
 #include <asm/cacheflush.h>
 #include <asm/iommu.h>
 
@@ -440,6 +441,7 @@ struct intel_iommu {
 	struct irq_domain *ir_msi_domain;
 #endif
 	struct device	*iommu_dev; /* IOMMU-sysfs device */
+	struct iommu_device iommu;  /* IOMMU core code handle */
 	int		node;
 	u32		flags;      /* Software defined flags */
 };