net/mlx5: block pop VLAN action on Tx
net/mlx5: block pop VLAN action on Tx

Add missing check in validation function of 'pop VLAN' action.
Action is not allowed for egress flow rules.

Fixes: b41e47da2592 ("net/mlx5: support pop flow action on VLAN header")
Cc: stable@dpdk.org

Signed-off-by: Dekel Peled <f1921780d3213ef78965aec36396441d9bf8894c@mellanox.com>
Acked-by: Ori Kam <dd654df5de18ba542acfaea52fe1a0799392087d@mellanox.com>
Acked-by: Viacheslav Ovsiienko <5b8db9bb93a9a9aefc8828f79604d1fe963a53dd@mellanox.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk