iommu/tegra-smmu: Clean up bus_set_iommu()

Stop calling bus_set_iommu() since it's now unnecessary, and simplify
the probe failure path accordingly.
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/13bb6baa6c4d74e95a12529e4eb1ddfb3885c3b5.1660572783.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

drivers/iommu/tegra-smmu.c

@@ -1083,8 +1083,8 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev,
 
 	/*
 	 * This is a bit of a hack. Ideally we'd want to simply return this
-	 * value. However the IOMMU registration process will attempt to add
-	 * all devices to the IOMMU when bus_set_iommu() is called. In order
+	 * value. However iommu_device_register() will attempt to add
+	 * all devices to the IOMMU before we get that far. In order
 	 * not to rely on global variables to track the IOMMU instance, we
 	 * set it here so that it can be looked up from the .probe_device()
 	 * callback via the IOMMU device's .drvdata field.
@@ -1138,32 +1138,15 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev,
 		return ERR_PTR(err);
 
 	err = iommu_device_register(&smmu->iommu, &tegra_smmu_ops, dev);
-	if (err)
-		goto remove_sysfs;
-
-	err = bus_set_iommu(&platform_bus_type, &tegra_smmu_ops);
-	if (err < 0)
-		goto unregister;
-
-#ifdef CONFIG_PCI
-	err = bus_set_iommu(&pci_bus_type, &tegra_smmu_ops);
-	if (err < 0)
-		goto unset_platform_bus;
-#endif
+	if (err) {
+		iommu_device_sysfs_remove(&smmu->iommu);
+		return ERR_PTR(err);
+	}
 
 	if (IS_ENABLED(CONFIG_DEBUG_FS))
 		tegra_smmu_debugfs_init(smmu);
 
 	return smmu;
-
-unset_platform_bus: __maybe_unused;
-	bus_set_iommu(&platform_bus_type, NULL);
-unregister:
-	iommu_device_unregister(&smmu->iommu);
-remove_sysfs:
-	iommu_device_sysfs_remove(&smmu->iommu);
-
-	return ERR_PTR(err);
 }
 
 void tegra_smmu_remove(struct tegra_smmu *smmu)