net/mlx5: E-Switch, Add support for offloading rules with no in_port

FTEs in global tables may match on packets from multiple in_ports.
Provide the capability to omit the in_port match condition.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>