net/mlx4_en: bug fix for the case of vlan id 0 and UP 0

When using vlan 0 and UP 0, vlan header wasn't placed.

Signed-off-by: Amir Vadai <amirv@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 807c218..7e76862 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -566,7 +566,8 @@
 		inl->byte_count = cpu_to_be32(1 << 31 | (skb->len - spc));
 	}
 	tx_desc->ctrl.vlan_tag = cpu_to_be16(*vlan_tag);
-	tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_VLAN * !!(*vlan_tag);
+	tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_VLAN *
+		(!!vlan_tx_tag_present(skb));
 	tx_desc->ctrl.fence_size = (real_size / 16) & 0x3f;
 }
 
@@ -677,7 +678,8 @@
 	/* Prepare ctrl segement apart opcode+ownership, which depends on
 	 * whether LSO is used */
 	tx_desc->ctrl.vlan_tag = cpu_to_be16(vlan_tag);
-	tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_VLAN * !!vlan_tag;
+	tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_VLAN *
+		!!vlan_tx_tag_present(skb);
 	tx_desc->ctrl.fence_size = (real_size / 16) & 0x3f;
 	tx_desc->ctrl.srcrb_flags = priv->ctrl_flags;
 	if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) {