[NIU]: Missing ->last_rx update.

Noticed by Paul Lodridge.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/niu.c b/drivers/net/niu.c
index 32ed87d..babb1ef 100644
--- a/drivers/net/niu.c
+++ b/drivers/net/niu.c
@@ -2241,6 +2241,8 @@
 	skb->protocol = eth_type_trans(skb, np->dev);
 	netif_receive_skb(skb);
 
+	np->dev->last_rx = jiffies;
+
 	return num_rcr;
 }