net/mlx5: E-Switch, Add ovs internal port mapping to metadata support

Adding infrastructure to map ovs internal port device to vport
match metadata to support offload of rules with internal port as
the filter device or as the destination device.

The infrastructure allows adding and removing internal port device
to an eswitch database and getting a unique vport metadata value to
be placed and match on in reg_c0 when offloading rules that are coming
from or going to an internal port.

The new int port metadata can be written to the source port register
in HW to indicate that current source port of the packet is the
internal port and not one of the actual HW vports (uplink or VF).
Using this method, it is possible to offload TC rules with an OVS
internal port as their destination port (overwriting the src vport
register) or as the filter port (matching on the value of the src
vport register and making sure it matches to the internal port's
value).

There is also a need to handle a miss case where the packet's
src port value was changed in HW to an internal port but a following
rule which matches on this new src port value wasn't found in HW.

In such case, the packet will be forwarded to the driver with
metadata which allows driver to restore the info of the internal
port's netdevice. Once this info is restored, the uplink driver
can forward the packet to the relevant netdevice in SW.

Signed-off-by: Ariel Levkovich <lariel@nvidia.com>
Reviewed-by: Vlad Buslov <vladbu@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>