PCI: Mark expected switch fall-through

There is a plan to build the kernel with -Wimplicit-fallthrough and
these places in the code produced warnings (W=1).  Fix them up.
Signed-off-by: Mathieu Malaterre <malat@debian.org>
[bhelgaas: squash into one patch, drop extra changelog detail]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci.c

@@ -861,7 +861,7 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
 		if ((pmcsr & PCI_PM_CTRL_STATE_MASK) == PCI_D3hot
 		 && !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET))
 			need_restore = true;
-		/* Fall-through: force to D0 */
+		/* Fall-through - force to D0 */
 	default:
 		pmcsr = 0;
 		break;
@@ -2260,7 +2260,7 @@ static pci_power_t pci_target_state(struct pci_dev *dev, bool wakeup)
 		case PCI_D2:
 			if (pci_no_d1d2(dev))
 				break;
-			/* else: fall through */
+			/* else, fall through */
 		default:
 			target_state = state;
 		}

drivers/pci/quirks.c

@@ -2138,7 +2138,7 @@ static void quirk_netmos(struct pci_dev *dev)
 		if (dev->subsystem_vendor == PCI_VENDOR_ID_IBM &&
 				dev->subsystem_device == 0x0299)
 			return;
-		/* else: fall through */
+		/* else, fall through */
 	case PCI_DEVICE_ID_NETMOS_9735:
 	case PCI_DEVICE_ID_NETMOS_9745:
 	case PCI_DEVICE_ID_NETMOS_9845: