net/mlx5: E-Switch, Rename egress config to generic name

Refactor vport egress config in offloads mode

Refactoring vport egress configuration in offloads mode that
includes egress prio tag configuration.
This makes code symmetric to ingress configuration.

Signed-off-by: Vu Pham <vuhuong@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>