net/mlx5e: Add a check for the return value from mlx5_port_set_eth_ptys

Since the documentation for mlx5_toggle_port_link states that it should
only be used after setting the port register, we add a check for the
return value from mlx5_port_set_eth_ptys to ensure the register was
successfully set before calling it.

Fixes: 667daeda ("net/mlx5e: Toggle link only after modifying port parameters")
Signed-off-by: Shahar Shitrit <shshitrit@nvidia.com>
Reviewed-by: Carolina Jubran <cjubran@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Link: https://patch.msgid.link/20240730061638.1831002-9-tariqt@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c

@@ -1409,7 +1409,12 @@ static int mlx5e_ethtool_set_link_ksettings(struct mlx5e_priv *priv,
 	if (!an_changes && link_modes == eproto.admin)
 		goto out;
 
-	mlx5_port_set_eth_ptys(mdev, an_disable, link_modes, ext);
+	err = mlx5_port_set_eth_ptys(mdev, an_disable, link_modes, ext);
+	if (err) {
+		netdev_err(priv->netdev, "%s: failed to set ptys reg: %d\n", __func__, err);
+		goto out;
+	}
+
 	mlx5_toggle_port_link(mdev);
 
 out: