net/mlx5e: Properly set steering match levels for offloaded TC decap rules

The match level computed by the driver gets to be wrong for decap
rules with wildcarded inner packet match such as:

tc filter add dev vxlan_sys_4789 protocol all parent ffff: prio 2 flower
       enc_dst_ip 192.168.0.9 enc_key_id 100 enc_dst_port 4789
       action tunnel_key unset
       action mirred egress redirect dev eth1

The FW errs for a missing matching meta-data indicator for the outer
headers (where we do have a match), and a wrong matching meta-data
indicator for the inner headers (where we don't have a match).

Fix that by taking into account the matching on the tunnel info and
relating the match level of the encapsulated packet to the firmware
inner headers indicator in case of decap.

As for vxlan we mandate a match on the tunnel udp dst port, and in general
we practically madndate a match on the source or dest ip for any IP tunnel,
the fix was done in a minimal manner around the tunnel match parsing code.

Fixes: d708f902

 ('net/mlx5e: Get the required HW match level while parsing TC flow matches')
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reported-by: Slava Ovsiienko <viacheslavo@mellanox.com>
Reviewed-by: Jianbo Liu <jianbol@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>