net/dsa/dsa.c: increment chip_index during of_node handling on dsa_of_probe()

Adding more than one chip on device-tree currently causes the probing
routine to always use the first chips data pointer.
Signed-off-by: Fabian Godehardt <fg@emlix.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/dsa.c

@@ -406,8 +406,9 @@ static int dsa_of_probe(struct platform_device *pdev)
 		goto out_free;
 	}
 
-	chip_index = 0;
+	chip_index = -1;
 	for_each_available_child_of_node(np, child) {
+		chip_index++;
 		cd = &pd->chip[chip_index];
 
 		cd->mii_bus = &mdio_bus->dev;