Staging: wlags49_h2: Fix build error when CONFIG_SYSFS is not set

I got a wlags49_h2 driver build error in linux-next when CONFIG_SYSFS is not set.

CC [M]  drivers/staging/wlags49_h2/wl_cs.o
In file included from drivers/staging/wlags49_h2/wl_cs.c:104:
drivers/staging/wlags49_h2/wl_sysfs.h: In function ‘register_wlags_sysfs’:
drivers/staging/wlags49_h2/wl_sysfs.h:5: error: parameter name omitted
drivers/staging/wlags49_h2/wl_sysfs.h: In function ‘unregister_wlags_sysfs’:
drivers/staging/wlags49_h2/wl_sysfs.h:6: error: parameter name omitted
make[1]: *** [drivers/staging/wlags49_h2/wl_cs.o] Error 1
make: *** [_module_drivers/staging/wlags49_h2] Error 2

This is due a wrong function definition (it does not include parameters names).
Signed-off-by: Javier Martinez Canillas <martinez.javier@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/wlags49_h2/wl_sysfs.h

@@ -2,6 +2,6 @@
 extern void register_wlags_sysfs(struct net_device *);
 extern void unregister_wlags_sysfs(struct net_device *);
 #else
-static void register_wlags_sysfs(struct net_device *) { return; };
-static void unregister_wlags_sysfs(struct net_device *) { return; };
+static inline void register_wlags_sysfs(struct net_device *net) { }
+static inline void unregister_wlags_sysfs(struct net_device *net) { }
 #endif