iommu/amd: Declare MSI and HT regions as reserved IOVA regions

This patch registers the MSI and HT regions as non mappable
reserved regions. They will be exposed in the iommu-group sysfs.

For direct-mapped regions let's also use iommu_alloc_resv_region().

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>