uio: add missing error codes

My static checker complains that "ret" could be uninitialized at the
end, which is true but it's more likely that it would be set to zero.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index bcc1fc0..fba021f 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -271,12 +271,16 @@
 			map_found = 1;
 			idev->map_dir = kobject_create_and_add("maps",
 							&idev->dev->kobj);
-			if (!idev->map_dir)
+			if (!idev->map_dir) {
+				ret = -ENOMEM;
 				goto err_map;
+			}
 		}
 		map = kzalloc(sizeof(*map), GFP_KERNEL);
-		if (!map)
+		if (!map) {
+			ret = -ENOMEM;
 			goto err_map_kobj;
+		}
 		kobject_init(&map->kobj, &map_attr_type);
 		map->mem = mem;
 		mem->map = map;
@@ -296,12 +300,16 @@
 			portio_found = 1;
 			idev->portio_dir = kobject_create_and_add("portio",
 							&idev->dev->kobj);
-			if (!idev->portio_dir)
+			if (!idev->portio_dir) {
+				ret = -ENOMEM;
 				goto err_portio;
+			}
 		}
 		portio = kzalloc(sizeof(*portio), GFP_KERNEL);
-		if (!portio)
+		if (!portio) {
+			ret = -ENOMEM;
 			goto err_portio_kobj;
+		}
 		kobject_init(&portio->kobj, &portio_attr_type);
 		portio->port = port;
 		port->portio = portio;