net/gianfar: drop recycled skbs on MTU change

The size for skbs which is added to the recycled list is using the
current descriptor size which is current MTU. gfar_new_skb() is also
using this size. So after changing or alteast increasing the MTU all
recycled skbs should be dropped.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index 4e97ca1..5d3763f 100644
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -1649,6 +1649,7 @@
 			sizeof(struct rxbd8) * priv->total_rx_ring_size,
 			priv->tx_queue[0]->tx_bd_base,
 			priv->tx_queue[0]->tx_bd_dma_base);
+	skb_queue_purge(&priv->rx_recycle);
 }
 
 void gfar_start(struct net_device *dev)
@@ -2088,7 +2089,6 @@
 
 	disable_napi(priv);
 
-	skb_queue_purge(&priv->rx_recycle);
 	cancel_work_sync(&priv->reset_task);
 	stop_gfar(dev);