net: mvpp2: Fix error return code in mvpp2_open()

Fix to return negative error code -ENOENT from invalid configuration
error handling case instead of 0, as done elsewhere in this function.

Fixes: 4bb04326 ("net: mvpp2: phylink support")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20201203141806.37966-1-wanghai38@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c

@@ -4426,6 +4426,7 @@ static int mvpp2_open(struct net_device *dev)
 	if (!valid) {
 		netdev_err(port->dev,
 			   "invalid configuration: no dt or link IRQ");
+		err = -ENOENT;
 		goto err_free_irq;
 	}