AMD IOMMU: introduce support for IVHD block type 11h

AMD IOMMU: introduce support for IVHD block type 11h

Along with the IVHD block type 10h, newer AMD platforms also come with
types 11h, which is a superset of the older one. Having multiple IVHD
block types in the same platform allows backward compatibility of newer
systems to work with existing drivers.  The driver should only parse
the highest-level (newest) type of IVHD block that it can support.
However, the current driver returns error when encounters with unknown
IVHD block type. This causes existing driver to unnecessarily fail IOMMU
initialization on new systems.

This patch introduces a new logic, which scans through IVRS table looking
for the highest-level supporsted IVHD block type. It also adds support
for the new IVHD block type 11h. More information about the IVHD type 11h
can be found in the AMD I/O Virtualization Technology (IOMMU) Specification
rev 2.62.

    http://support.amd.com/TechDocs/48882_IOMMU.pdf

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>