iwlwifi: fix software rf_kill problem when interface is down

The patch fixes the problem that software rf_kill messes up the
card status when it is disabled if the interface is down.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index 72279e0..d0084bc 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -2875,7 +2875,8 @@
 		return;
 	}
 
-	queue_work(priv->workqueue, &priv->restart);
+	if (priv->is_open)
+		queue_work(priv->workqueue, &priv->restart);
 	return;
 }