mt76: fix compilation warning in mt76_eeprom_override()

Fix the following compilation warning in mt76_eeprom_override routine
when CONFIG_OF is not set and label 'out' is not actually used

drivers/net/wireless/mediatek/mt76/eeprom.c: In function ‘mt76_eeprom_override’:
drivers/net/wireless/mediatek/mt76/eeprom.c:100:1: warning: label ‘out’ defined but not used [-Wunused-label]
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -87,17 +87,14 @@ mt76_eeprom_override(struct mt76_dev *dev)
 {
 #ifdef CONFIG_OF
 	struct device_node *np = dev->dev->of_node;
-	const u8 *mac;
-
-	if (!np)
-		goto out;
+	const u8 *mac = NULL;
 
+	if (np)
 		mac = of_get_mac_address(np);
-	if (!IS_ERR(mac))
+	if (!IS_ERR_OR_NULL(mac))
 		ether_addr_copy(dev->macaddr, mac);
 #endif
 
-out:
 	if (!is_valid_ether_addr(dev->macaddr)) {
 		eth_random_addr(dev->macaddr);
 		dev_info(dev->dev,