cw1200: Fix spurious BUG_ON() trigger when starting AP mode.

There's an underlying race condition with the unjoin_work() call that is
sometimes triggered depending on scheduling order and the phase of the
moon.  This doesn't fix the race condition, but it does remove the
ill-advised BUG_ON() call in an easily-recoverable situation.
Signed-off-by: Solomon Peachy <pizza@shaftnet.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/cw1200/sta.c

@@ -1406,11 +1406,8 @@ static void cw1200_do_unjoin(struct cw1200_common *priv)
 	if (!priv->join_status)
 		goto done;
 
-	if (priv->join_status > CW1200_JOIN_STATUS_IBSS) {
-		wiphy_err(priv->hw->wiphy, "Unexpected: join status: %d\n",
-			  priv->join_status);
-		BUG_ON(1);
-	}
+	if (priv->join_status == CW1200_JOIN_STATUS_AP)
+		goto done;
 
 	cancel_work_sync(&priv->update_filtering_work);
 	cancel_work_sync(&priv->set_beacon_wakeup_period_work);