PCI: pciehp: Don't turn slot off when hot-added device already exists

If we found device already exists during hot add device, we should leave
it, not turn the slot off.

Signed-off-by: Yijing Wang <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>

drivers/pci/hotplug/pciehp_ctrl.c

···
 	if (retval) {
 		ctrl_err(ctrl, "Cannot add device at %04x:%02x:00\n",
 			 pci_domain_nr(parent), parent->number);
-		goto err_exit;
+		if (retval != -EEXIST)
+			goto err_exit;
 	}
 
 	pciehp_green_led_on(p_slot);

drivers/pci/hotplug/pciehp_pci.c

···
 			 "at %04x:%02x:00, cannot hot-add\n", pci_name(dev),
 			 pci_domain_nr(parent), parent->number);
 		pci_dev_put(dev);
-		ret = -EINVAL;
+		ret = -EEXIST;
 		goto out;
 	}