net/mlx4_en: Validate VLAN IDs provided in ethtool flow steering rules

When attaching flow steering rules via Ethtool accept only valid vlans IDs e.g
in the range: [0,4095].

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>