net: mvpp2: fix port list indexing

The private port_list array has a list of pointers to mvpp2_port
instances. This list is allocated given the number of ports enabled in
the device tree, but the pointers are set using the port-id property. If
on a single port is enabled, the port_list array will be of size 1, but
when registering the port, if its id is not 0 the driver will crash.
Other crashes were encountered in various situations.

This fixes the issue by using an index not equal to the value of the
port-id property.

Fixes: 3f518509 ("ethernet: Add new driver for Marvell Armada 375 network unit")
Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Yan Markman <ymarkman@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2.c

@@ -7504,7 +7504,7 @@ static void mvpp2_port_copy_mac_addr(struct net_device *dev, struct mvpp2 *priv,
 /* Ports initialization */
 static int mvpp2_port_probe(struct platform_device *pdev,
 			    struct device_node *port_node,
-			    struct mvpp2 *priv)
+			    struct mvpp2 *priv, int index)
 {
 	struct device_node *phy_node;
 	struct phy *comphy;
@@ -7678,7 +7678,7 @@ static int mvpp2_port_probe(struct platform_device *pdev,
 	}
 	netdev_info(dev, "Using %s mac address %pM\n", mac_from, dev->dev_addr);
 
-	priv->port_list[id] = port;
+	priv->port_list[index] = port;
 	return 0;
 
 err_free_port_pcpu:
@@ -8013,10 +8013,12 @@ static int mvpp2_probe(struct platform_device *pdev)
 	}
 
 	/* Initialize ports */
+	i = 0;
 	for_each_available_child_of_node(dn, port_node) {
-		err = mvpp2_port_probe(pdev, port_node, priv);
+		err = mvpp2_port_probe(pdev, port_node, priv, i);
 		if (err < 0)
 			goto err_mg_clk;
+		i++;
 	}
 
 	platform_set_drvdata(pdev, priv);