net: mvpp2: Fix a memory leak in error handling path

if 'devm_kzalloc()' fails, we should release resources allocated so far,
just as done a few lines below.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2.c

@@ -5971,8 +5971,10 @@ static int mvpp2_port_init(struct mvpp2_port *port)
 		struct mvpp2_tx_queue *txq;
 
 		txq = devm_kzalloc(dev, sizeof(*txq), GFP_KERNEL);
-		if (!txq)
-			return -ENOMEM;
+		if (!txq) {
+			err = -ENOMEM;
+			goto err_free_percpu;
+		}
 
 		txq->pcpu = alloc_percpu(struct mvpp2_txq_pcpu);
 		if (!txq->pcpu) {