powerpc/pseries: Checking for pdn->parent is redundant

The device tree root is never a pci bus, and will not have a
PCI_DN(pdn), so the check for PCI_DN added in
650f7b3b makes the check for pdn->parent
redundant and it can be removed.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/pseries/iommu.c

@@ -530,10 +530,7 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
 	}
 	pr_debug("  parent is %s\n", pdn->full_name);
 
-	/* Check for parent == NULL so we don't try to setup the empty EADS
-	 * slots on POWER4 machines.
-	 */
-	if (dma_window == NULL || pdn->parent == NULL) {
+	if (dma_window == NULL) {
 		pr_debug("  no dma window for device, linking to parent\n");
 		set_iommu_table_base(&dev->dev, PCI_DN(pdn)->iommu_table);
 		return;