iommu: Retire map/unmap ops

With everyone now implementing the new interfaces, clean up the last
remnants of the old map/unmap ops and simplify the calling logic again.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/d2afdf13b2fbf537713c3ec642dfd49d16dd9e6a.1694525662.git.robin.murphy@arm.com


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