net/mlx5: fix set VLAN ID/PCP in new header

net/mlx5: fix set VLAN ID/PCP in new header

Currently if user want to set VLAN id/pcp on an about to be pushed VLAN
header, the of_set_vlan_vid/of_set_vlan_pcp must be present _before_
action of_push_vlan:

[1] ... actions of_set_vlan_vid vlan_vid 2 / of_push_vlan ...

This is misleading because people think rule [1] intends to set VLAN id
on the existing VLAN header and then push one new VLAN header on top of
it.

A more natual way to set VLAN id/pcp on an to be pushed VLAN header
should be:

[2] ... actions of_push_vlan / of_set_vlan_vid vlan_vid 2 / ...

Fixes: a5f2da0b816b ("net/mlx5: support modify VLAN ID on new VLAN header")
Fixes: 68fad3635042 ("net/mlx5: support modifying VLAN priority on VLAN header")
Signed-off-by: Xiaoyu Min <jackmin@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>