parisc: fix wrong assumption about bus->self

Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> posted a patch series
to linux-pci to fix a wrong assumption about pci_bus->self==NULL for
all PCI host bus controllers. While PARISC platforms to not behave
this way, I prefer to have the code consistent across architectures.
The following patch replaces pci_bus->self with pci_bus->parent when
used as a test to check for "root bus controller".

Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
diff --git a/drivers/parisc/iosapic.c b/drivers/parisc/iosapic.c
index 0797659..1cdfdea 100644
--- a/drivers/parisc/iosapic.c
+++ b/drivers/parisc/iosapic.c
@@ -487,7 +487,7 @@
 	}
 
 	/* Check if pcidev behind a PPB */
-	if (NULL != pcidev->bus->self) {
+	if (pcidev->bus->parent) {
 		/* Convert pcidev INTR_PIN into something we
 		** can lookup in the IRT.
 		*/
@@ -523,10 +523,9 @@
 #endif /* PCI_BRIDGE_FUNCS */
 
 		/*
-		** Locate the host slot the PPB nearest the Host bus
-		** adapter.
-		*/
-		while (NULL != p->parent->self)
+		 * Locate the host slot of the PPB.
+		 */
+		while (p->parent->parent)
 			p = p->parent;
 
 		intr_slot = PCI_SLOT(p->self->devfn);