w5100: using eth_hw_addr_random() for random MAC and set device flag

Using eth_hw_addr_random() to generate a random Ethernet address
(MAC) to be used by a net device and set addr_assign_type.
Not need to duplicating its implementation.

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/wiznet/w5100.c

@@ -637,8 +637,7 @@ static int __devinit w5100_hw_probe(struct platform_device *pdev)
 	if (data && is_valid_ether_addr(data->mac_addr)) {
 		memcpy(ndev->dev_addr, data->mac_addr, ETH_ALEN);
 	} else {
-		eth_random_addr(ndev->dev_addr);
-		ndev->addr_assign_type |= NET_ADDR_RANDOM;
+		eth_hw_addr_random(ndev);
 	}
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);