vhost-vdpa: Use iommu_paging_domain_alloc()

Replace iommu_domain_alloc() with iommu_paging_domain_alloc().

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20240610085555.88197-5-baolu.lu@linux.intel.com


Signed-off-by: Will Deacon <will@kernel.org>