powerpc/viobus: Free TCE table on device release

Release the TCE table as the XXX suggests, except on FW_FEATURE_ISERIES,
where the tables are allocated globally and reused.

Signed-off-by: Milton Miller <[e-mail]>
Signed-off-by: Nishanth Aravamudan <[e-mail]>
Signed-off-by: Benjamin Herrenschmidt <[e-mail]>

arch/powerpc/kernel/vio.c

···
 /* vio_dev refcount hit 0 */
 static void __devinit vio_dev_release(struct device *dev)
 {
-	/* XXX should free TCE table */
+	struct iommu_table *tbl = get_iommu_table_base(dev);
+
+	/* iSeries uses a common table for all vio devices */
+	if (!firmware_has_feature(FW_FEATURE_ISERIES) && tbl)
+		iommu_free_table(tbl, dev->of_node ?
+			dev->of_node->full_name : dev_name(dev));
 	of_node_put(dev->of_node);
 	kfree(to_vio_dev(dev));
 }