iommu/vt-d: Add nested domain allocation

This adds the support for IOMMU_HWPT_DATA_VTD_S1 type. And 'nested_parent'
is added to mark the nested parent domain to sanitize the input parent domain.

Link: https://lore.kernel.org/r/20231026044216.64964-8-yi.l.liu@intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>