lantiq: fix compilation warning in lantiq_etop_init

Commit c5cc3d96109a ("lantiq: Change the data-type of mac address in ETOP driver")
changed the type of the mac variable. Since then, the priv->mac check always evaluates
as true, so this check can be removed.

This fix compilation warning:
drivers/net/ethernet/lantiq_etop.c: In function 'ltq_etop_init':
drivers/net/ethernet/lantiq_etop.c:775:13: warning: the comparison will always evaluate as 'true' for the address of 'mac' will never be NULL [-Waddress]
  775 |         if (priv->mac && !is_valid_ether_addr(mac.sa_data))
      |             ^~~~
drivers/net/ethernet/lantiq_etop.c:157:23: note: 'mac' declared here
  157 |         unsigned char mac[6];
      |
cc1: all warnings being treated as errors

Fixes: c5cc3d96109a ("lantiq: Change the data-type of mac address in ETOP driver")
Signed-off-by: Aleksander Jan Bajkowski <[email protected]>
[ fix wrong fixes tag format ]
Signed-off-by: Christian Marangi <[email protected]>

target/linux/lantiq/patches-5.15/0035-owrt-lantiq-wifi-and-ethernet-eeprom-handling.patch

@@ -210,7 +210,7 @@ Signed-off-by: John Crispin <[email protected]>
 -	memcpy(&mac, &priv->pldata->mac, sizeof(struct sockaddr));
 +	memcpy(&mac.sa_data, ltq_get_eth_mac(), ETH_ALEN);
 +
-+	if (priv->mac && !is_valid_ether_addr(mac.sa_data))
++	if (!is_valid_ether_addr(mac.sa_data))
 +		memcpy(&mac.sa_data, priv->mac, ETH_ALEN);
 +
  	if (!is_valid_ether_addr(mac.sa_data)) {