Input: gameport - use IS_REACHABLE() instead of open-coding it

Replace an open-coded preprocessor conditional with an equivalent helper.
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/ZKYLLmsdCH0Gp7TO@google.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

include/linux/gameport.h

@@ -63,7 +63,7 @@ struct gameport_driver {
 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode);
 void gameport_close(struct gameport *gameport);
 
-#if defined(CONFIG_GAMEPORT) || (defined(MODULE) && defined(CONFIG_GAMEPORT_MODULE))
+#if IS_REACHABLE(CONFIG_GAMEPORT)
 
 void __gameport_register_port(struct gameport *gameport, struct module *owner);
 /* use a define to avoid include chaining to get THIS_MODULE */