iommufd/selftest: Test IOMMU_HWPT_SET_DIRTY_TRACKING

Change mock_domain to supporting dirty tracking and add tests to exercise
the new SET_DIRTY_TRACKING API in the iommufd_dirty_tracking selftest
fixture.

Link: https://lore.kernel.org/r/20231024135109.73787-16-joao.m.martins@oracle.com


Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>