net/mlx5: add flow table tunnel offload attribute

net/mlx5: add flow table tunnel offload attribute

As flow table is shared between the ports in the same shared IB device,
flow table may be created by one port and released by other port.

Currently, the tunnel offloading active check in flow table release is
based on the port which release the flow table. Since the flow table
create port and release port may have different tunnel offloading
configuration, it will cause invalid tunnel offloading release or
tunnel offloading resource leaks.

Add the flow table tunnel offloading attribute to indicate the flow
table has tunnel offloading resource or not to avoid wrong tunnel
offloading operation.

Signed-off-by: Suanming Mou <suanmingm@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>