iommu/amd: Set AMD iommu callbacks for amba bus

AMD Uart DMA belongs to ACPI HID type device, and its driver
is basing on AMBA Bus, need also IOMMU support.

This patch is just to set the AMD iommu callbacks for amba bus.

Signed-off-by: Wan Zongshun <Vincent.Wan@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>