ACPI: PCI: use positive logic to simplify code

This doesn't change anything functionally; it just changes tests
so we test for success instead of failure.  This makes the code
read more easily and allows us to remove the "!entry" in the while
loop condition.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/pci_irq.c

@@ -384,16 +384,15 @@ acpi_pci_irq_lookup(struct pci_dev *dev, int pin)
 	struct acpi_prt_entry *entry;
 
 	entry = acpi_pci_irq_find_prt_entry(dev, pin);
-	if (!entry) {
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No %s[%c] _PRT entry\n",
+	if (entry) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %s[%c] _PRT entry\n",
 				  pci_name(dev), pin_name(pin)));
-		return NULL;
+		return entry;
 	}
 
-	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %s[%c] _PRT entry\n",
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No %s[%c] _PRT entry\n",
 			  pci_name(dev), pin_name(pin)));
-
-	return entry;
+	return NULL;
 }
 
 static struct acpi_prt_entry *
@@ -408,7 +407,7 @@ acpi_pci_irq_derive(struct pci_dev *dev, int pin)
 	 * Attempt to derive an IRQ for this device from a parent bridge's
 	 * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
 	 */
-	while (!entry && bridge->bus->self) {
+	while (bridge->bus->self) {
 		pin = (((pin - 1) + PCI_SLOT(bridge->devfn)) % 4) + 1;
 		bridge = bridge->bus->self;
 
@@ -425,18 +424,18 @@ acpi_pci_irq_derive(struct pci_dev *dev, int pin)
 		}
 
 		entry = acpi_pci_irq_lookup(bridge, pin);
+		if (entry) {
+			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+					 "Derived GSI for %s INT %c from %s\n",
+					 pci_name(dev), pin_name(orig_pin),
+					 pci_name(bridge)));
+			return entry;
+		}
 	}
 
-	if (!entry) {
-		dev_warn(&dev->dev, "can't derive routing for PCI INT %c\n",
-			 pin_name(orig_pin));
-		return NULL;
-	}
-
-	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Derived GSI for %s INT %c from %s\n",
-			  pci_name(dev), pin_name(orig_pin), pci_name(bridge)));
-
-	return entry;
+	dev_warn(&dev->dev, "can't derive routing for PCI INT %c\n",
+		 pin_name(orig_pin));
+	return NULL;
 }
 
 /*