ethernet: manually convert memcpy(dev_addr,..., sizeof(addr))

A handful of drivers use sizeof(addr) for the size of
the address, after manually confirming the size is
indeed 6 convert them to eth_hw_addr_set().

Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Petko Manolov <petkan@nucleusys.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/cadence/macb_main.c

@@ -313,7 +313,7 @@ static void macb_get_hwaddr(struct macb *bp)
 		addr[5] = (top >> 8) & 0xff;
 
 		if (is_valid_ether_addr(addr)) {
-			memcpy(bp->dev->dev_addr, addr, sizeof(addr));
+			eth_hw_addr_set(bp->dev, addr);
 			return;
 		}
 	}