PCI: Make pci_bus_add_device() void

pci_bus_add_device() always returns 0, so there's no point in returning
anything at all.  Make it a void function and remove the tests of the
return value from the callers.

[bhelgaas: changelog, remove unused "err" from i82875p_setup_overfl_dev()]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index c5e082f..91ef69a 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -642,8 +642,7 @@
 			dev = pci_scan_single_device(bus, 0);
 			if (dev) {
 				pci_bus_assign_resources(bus);
-				if (pci_bus_add_device(dev))
-					pr_err("Unable to hotplug wifi\n");
+				pci_bus_add_device(dev);
 			}
 		} else {
 			dev = pci_get_slot(bus, 0);