net/mlx5: prevent ioctl failure log flooding

[ upstream commit 84ba1440c5dff8d716c1a2643aa3eb5e806619ff ]

The following log is printed in WARNING severity:

mlx5_net: port 1 ioctl(SIOCETHTOOL, ETHTOOL_GPAUSEPARAM) failed:
    Operation not supported

Reduce the severity to DEBUG to prevent this log from flooding
when there are hundreds of ports probed without supporting this
flow ctrl query.

Fixes: 1256805 ("net/mlx5: move Linux-specific functions")

Signed-off-by: Eli Britstein <elibr@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

drivers/net/mlx5/linux/mlx5_ethdev_os.c

@@ -670,7 +670,7 @@ mlx5_dev_get_flow_ctrl(struct rte_eth_dev *dev, struct rte_eth_fc_conf *fc_conf)
 	ifr.ifr_data = (void *)&ethpause;
 	ret = mlx5_ifreq(dev, SIOCETHTOOL, &ifr);
 	if (ret) {
-		DRV_LOG(WARNING,
+		DRV_LOG(DEBUG,
 			"port %u ioctl(SIOCETHTOOL, ETHTOOL_GPAUSEPARAM) failed:"
 			" %s",
 			dev->data->port_id, strerror(rte_errno));