iommu/amd: Add support for fast IOTLB flushing

Since AMD IOMMU driver currently flushes all TLB entries
when page size is more than one, use the same interface
for both iommu_ops.flush_iotlb_all() and iommu_ops.iotlb_sync().

Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>