iommu: Remove sva handle list

The struct sva_iommu represents an association between an SVA domain and
a PASID of a device. It's stored in the iommu group's pasid array and also
tracked by a list in the per-mm data structure. Removes duplicate tracking
of sva_iommu by eliminating the list.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240702063444.105814-3-baolu.lu@linux.intel.com


Signed-off-by: Will Deacon <will@kernel.org>