enetc: Fix an off by one in enetc_setup_tc_txtime()

The priv->tx_ring[] has 16 elements but only priv->num_tx_rings are
set up, the rest are NULL.  This ">" comparison should be ">=" to avoid
a potential crash.

Fixes: 0d08c9ec ("enetc: add support time specific departure base on the qos etf")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/enetc/enetc_qos.c

@@ -315,7 +315,7 @@ int enetc_setup_tc_txtime(struct net_device *ndev, void *type_data)
 
 	tc = qopt->queue;
 
-	if (tc < 0 || tc > priv->num_tx_rings)
+	if (tc < 0 || tc >= priv->num_tx_rings)
 		return -EINVAL;
 
 	/* Do not support TXSTART and TX CSUM offload simutaniously */