ethernet: seeq/ether3: don't write directly to netdev->dev_addr

netdev->dev_addr is const now.

Compile tested rpc_defconfig w/ GCC 8.5.

Fixes: adeef3e32146 ("net: constify netdev->dev_addr")
Signed-off-by: Jakub Kicinski <[e-mail]>
Reviewed-by: Russell King (Oracle) <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/seeq/ether3.c

···
 	const struct ether3_data *data = id->data;
 	struct net_device *dev;
 	int bus_type, ret;
+	u8 addr[ETH_ALEN];
 
 	ether3_banner();
 
···
 	priv(dev)->seeq = priv(dev)->base + data->base_offset;
 	dev->irq = ec->irq;
 
-	ether3_addr(dev->dev_addr, ec);
+	ether3_addr(addr, ec);
+	eth_hw_addr_set(dev, addr);
 
 	priv(dev)->dev = dev;
 	timer_setup(&priv(dev)->timer, ether3_ledoff, 0);