dsa: Use ether_addr_copy

Use ether_addr_copy instead of memcpy(a, b, ETH_ALEN) to
save some cycles on arm and powerpc.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/dsa/slave.c

@@ -156,7 +156,7 @@ static int dsa_slave_set_mac_address(struct net_device *dev, void *a)
 		dev_uc_del(master, dev->dev_addr);
 
 out:
-	memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
+	ether_addr_copy(dev->dev_addr, addr->sa_data);
 
 	return 0;
 }