airport: remove useless return in a function returning void

Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/orinoco/airport.c

@@ -279,7 +279,7 @@ init_airport(void)
 static void __exit
 exit_airport(void)
 {
-	return macio_unregister_driver(&airport_driver);
+	macio_unregister_driver(&airport_driver);
 }
 
 module_init(init_airport);