iommu: Remove aux-domain related interfaces and iommu_ops

The aux-domain related interfaces and iommu_ops are not referenced
anywhere in the tree. We've also reached a consensus to redesign it
based the new iommufd framework. Remove them to avoid dead code.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20220216025249.3459465-5-baolu.lu@linux.intel.com


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