iwmc3200wifi: fix busted iwm_debugfs_init definition

Looks like we missed removing the return statement in the non-CONFIG_IWM_DEBUG
dummy implementation of iwm_debugfs_init...
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwmc3200wifi/debug.h

@@ -116,10 +116,7 @@ struct iwm_debugfs {
 void iwm_debugfs_init(struct iwm_priv *iwm);
 void iwm_debugfs_exit(struct iwm_priv *iwm);
 #else
-static inline void iwm_debugfs_init(struct iwm_priv *iwm)
-{
-	return 0;
-}
+static inline void iwm_debugfs_init(struct iwm_priv *iwm) {}
 static inline void iwm_debugfs_exit(struct iwm_priv *iwm) {}
 #endif