drm/nouveau/tegra: Use iommu_paging_domain_alloc()

In nvkm_device_tegra_probe_iommu(), a paging domain is allocated for @dev
and attached to it on success. Use iommu_paging_domain_alloc() to make it
explicit.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20241009041147.28391-4-baolu.lu@linux.intel.com


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