drm/nouveau/device: Get right pgsize_bitmap of iommu_domain

The supported page sizes of an iommu_domain are saved in the pgsize_bitmap
field. Retrieve the value from the right place.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20211218074546.1772553-1-baolu.lu@linux.intel.comReviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20220216025249.3459465-7-baolu.lu@linux.intel.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c

@@ -133,7 +133,7 @@ nvkm_device_tegra_probe_iommu(struct nvkm_device_tegra *tdev)
 		 * or equal to the system's PAGE_SIZE, with a preference if
 		 * both are equal.
 		 */
-		pgsize_bitmap = tdev->iommu.domain->ops->pgsize_bitmap;
+		pgsize_bitmap = tdev->iommu.domain->pgsize_bitmap;
 		if (pgsize_bitmap & PAGE_SIZE) {
 			tdev->iommu.pgshift = PAGE_SHIFT;
 		} else {