iommu/exynos: Clean up bus_set_iommu()

Stop calling bus_set_iommu() since it's now unnecessary, and simplify
the init failure path accordingly.
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/d7477ef546479300217ca7bccb44da8b02715a07.1660572783.git.robin.murphy@arm.comSigned-off-by: NJoerg Roedel <jroedel@suse.de>

drivers/iommu/exynos-iommu.c

@@ -1446,16 +1446,7 @@ static int __init exynos_iommu_init(void)
 		goto err_zero_lv2;
 	}
 
-	ret = bus_set_iommu(&platform_bus_type, &exynos_iommu_ops);
-	if (ret) {
-		pr_err("%s: Failed to register exynos-iommu driver.\n",
-								__func__);
-		goto err_set_iommu;
-	}
-
 	return 0;
-err_set_iommu:
-	kmem_cache_free(lv2table_kmem_cache, zero_lv2_table);
 err_zero_lv2:
 	platform_driver_unregister(&exynos_sysmmu_driver);
 err_reg_driver: