Documentation: userspace-api: iommufd: Update FAULT and VEVENTQ

With the introduction of the new objects, update the doc to reflect that.

Link: https://patch.msgid.link/r/09829fbc218872d242323d8834da4bec187ce6f4.1741719725.git.nicolinc@nvidia.com


Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>