PCI: ZT5550 CPCI Hotplug driver fix

cc: Philip Guo <pg@cs.stanford.edu>

Here's a small patch against the current git tree for the ZT5550 CPCI 
hotplug driver to fix an issue with port freeing that Philip Guo found.
Signed-off-by: NScott Murray <scottm@somanetworks.com>
Signed-off-by: NKristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/pci/hotplug/cpcihp_zt5550.c

@@ -296,13 +296,17 @@ static struct pci_driver zt5550_hc_driver = {
 static int __init zt5550_init(void)
 {
 	struct resource* r;
+	int rc;
 
 	info(DRIVER_DESC " version: " DRIVER_VERSION);
 	r = request_region(ENUM_PORT, 1, "#ENUM hotswap signal register");
 	if(!r)
 		return -EBUSY;
 
-	return pci_register_driver(&zt5550_hc_driver);
+	rc = pci_register_driver(&zt5550_hc_driver);
+	if(rc < 0)
+		release_region(ENUM_PORT, 1);
+	return rc;
 }
 
 static void __exit