dpaa2-eth: Fix minor bug in ethtool stats reporting

Don't print error message for a successful return value.

Fixes: d84c3a4 ("dpaa2-eth: Add new DPNI statistics counters")

Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c

@@ -216,7 +216,7 @@ static void dpaa2_eth_get_ethtool_stats(struct net_device *net_dev,
 		if (err == -EINVAL)
 			/* Older firmware versions don't support all pages */
 			memset(&dpni_stats, 0, sizeof(dpni_stats));
-		else
+		else if (err)
 			netdev_warn(net_dev, "dpni_get_stats(%d) failed\n", j);
 
 		num_cnt = dpni_stats_page_size[j] / sizeof(u64);