net: ethernet: ax88796: support generating a random mac address

Instead of falling back to 00:00:00:00:00:00 generate a random address
if none is provided via platform data or from the device's register
space.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/8390/ax88796.c

@@ -723,6 +723,12 @@ static int ax_init_dev(struct net_device *dev)
 	    ax->plat->mac_addr)
 		memcpy(dev->dev_addr, ax->plat->mac_addr, ETH_ALEN);
 
+	if (!is_valid_ether_addr(dev->dev_addr)) {
+		eth_hw_addr_random(dev);
+		dev_info(&dev->dev, "Using random MAC address: %pM\n",
+			 dev->dev_addr);
+	}
+
 	ax_reset_8390(dev);
 
 	ei_local->name = "AX88796";