iommu/vt-d: Remove unused fields in svm structures

They aren't used anywhere. Remove them to avoid dead code.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20230109014955.147068-3-baolu.lu@linux.intel.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>