PCI: Warn about failures instead of "must_check" functions

These places capture return values to avoid "must_check" warnings,
but we didn't *do* anything with the return values, which causes
"set but not used" warnings.  We might as well do something instead
of just trying to evade the "must_check" warnings.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c
index ac6412f..c1e9284 100644
--- a/drivers/pci/slot.c
+++ b/drivers/pci/slot.c
@@ -377,14 +377,17 @@
 {
 	struct hotplug_slot *slot = pci_slot->hotplug;
 	struct kobject *kobj = NULL;
-	int no_warn;
+	int ret;
 
 	if (!slot || !slot->ops)
 		return;
 	kobj = kset_find_obj(module_kset, slot->ops->mod_name);
 	if (!kobj)
 		return;
-	no_warn = sysfs_create_link(&pci_slot->kobj, kobj, "module");
+	ret = sysfs_create_link(&pci_slot->kobj, kobj, "module");
+	if (ret)
+		dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n",
+			ret);
 	kobject_put(kobj);
 }
 EXPORT_SYMBOL_GPL(pci_hp_create_module_link);