sfc: Use canonical pointer type for MAC address in efx_set_mac_address()

Functions such as is_valid_ether_addr() expect u8 *, so use that
instead of char *.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Shradha Shah <sshah@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/efx.c

@@ -2113,7 +2113,7 @@ static int efx_set_mac_address(struct net_device *net_dev, void *data)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
 	struct sockaddr *addr = data;
-	char *new_addr = addr->sa_data;
+	u8 *new_addr = addr->sa_data;
 
 	if (!is_valid_ether_addr(new_addr)) {
 		netif_err(efx, drv, efx->net_dev,