net/mlx5: Lag, Fix for loop when checking lag

The cited commit adds a for loop to check if each port supports lag
or not. But dev is not initialized correctly. Fix it by initializing
dev for each iteration.

Fixes: e87c6a83 ("net/mlx5: E-switch, Fix duplicate lag creation")
Signed-off-by: Chris Mi <cmi@nvidia.com>
Reported-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Link: https://lore.kernel.org/r/20221129093006.378840-2-saeed@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -700,11 +700,13 @@ static bool mlx5_lag_check_prereq(struct mlx5_lag *ldev)
 			return false;
 
 #ifdef CONFIG_MLX5_ESWITCH
-	dev = ldev->pf[MLX5_LAG_P1].dev;
-	for (i = 0; i  < ldev->ports; i++)
+	for (i = 0; i < ldev->ports; i++) {
+		dev = ldev->pf[i].dev;
 		if (mlx5_eswitch_num_vfs(dev->priv.eswitch) && !is_mdev_switchdev_mode(dev))
 			return false;
+	}
 
+	dev = ldev->pf[MLX5_LAG_P1].dev;
 	mode = mlx5_eswitch_mode(dev);
 	for (i = 0; i < ldev->ports; i++)
 		if (mlx5_eswitch_mode(ldev->pf[i].dev) != mode)