RDMA/mlx5: Enable decap and packet reformat on FDB

If FDB flow tables support decap operation, enable it on creation,
This allows to perform decapsulation of tunnelled packets by steering
rules. If FDB flow tables support reformat operation, enable it on
creation as well.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>