iommu/viommu: Add cache_invalidate to iommufd_viommu_ops

iommu/viommu: Add cache_invalidate to iommufd_viommu_ops

This per-vIOMMU cache_invalidate op is like the cache_invalidate_user op
in struct iommu_domain_ops, but wider, supporting device cache (e.g. PCI
ATC invaldiations).

Link: https://patch.msgid.link/r/90138505850fa6b165135e78a87b4cc7022869a4.1730836308.git.nicolinc@nvidia.com
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>