rtl8187: Fix for kernel oops when unloading with LEDs enabled

When rtl8187 is unloaded and CONFIG_RTL8187_LEDS is set, the kernel
may oops when the module is unloaded as the workqueue for led_on was
not being cancelled.

This patch fixes the problem reported in
http://marc.info/?l=linux-wireless&m=124742957615781&w=2.

Reported-by: Gábor Stefanik <netrolller.3d@gmail.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtl818x/rtl8187_leds.c

@@ -208,11 +208,12 @@ void rtl8187_leds_exit(struct ieee80211_hw *dev)
 {
 	struct rtl8187_priv *priv = dev->priv;
 
-	rtl8187_unregister_led(&priv->led_tx);
 	/* turn the LED off before exiting */
 	queue_delayed_work(dev->workqueue, &priv->led_off, 0);
 	cancel_delayed_work_sync(&priv->led_off);
+	cancel_delayed_work_sync(&priv->led_on);
 	rtl8187_unregister_led(&priv->led_rx);
+	rtl8187_unregister_led(&priv->led_tx);
 }
 #endif /* def CONFIG_RTL8187_LED */