iommu/vt-d: Add domain_flush_pasid_iotlb()

iommu/vt-d: Add domain_flush_pasid_iotlb()

The VT-d spec requires to use PASID-based-IOTLB invalidation descriptor
to invalidate IOTLB and the paging-structure caches for a first-stage
page table. Add a generic helper to do this.

RID2PASID is used if the domain has been attached to a physical device,
otherwise real PASIDs that the domain has been attached to will be used.
The 'real' PASID attachment is handled in the subsequent change.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20230802212427.1497170-4-jacob.jun.pan@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>