net: wireless: support of_get_mac_address new ERR_PTR error

There was NVMEM support added to of_get_mac_address, so it could now return
ERR_PTR encoded error values, so we need to adjust all current users of
of_get_mac_address to this new fact.

Signed-off-by: Petr Štetiar <ynezz@true.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wireless/mediatek/mt76/eeprom.c

@@ -94,7 +94,7 @@ mt76_eeprom_override(struct mt76_dev *dev)
 		return;
 
 	mac = of_get_mac_address(np);
-	if (mac)
+	if (!IS_ERR(mac))
 		memcpy(dev->macaddr, mac, ETH_ALEN);
 #endif