net/mlx5: E-Switch, properly handle ingress tagged packets on VST

Fix SRIOV VST mode behavior to insert cvlan when a guest tag is already
present in the frame. Previous VST mode behavior was to drop packets or
override existing tag, depending on the device version.

In this patch we fix this behavior by correctly building the HW steering
rule with a push vlan action, or for older devices we ask the FW to stack
the vlan when a vlan is already present.

Fixes: 07bab950 ("net/mlx5: E-Switch, Refactor eswitch ingress acl codes")
Fixes: dfcb1ed3

 ("net/mlx5: E-Switch, Vport ingress/egress ACLs rules for VST mode")
Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>