net/sched: act_tunnel_key: Don't dump dst port if it wasn't set

net/sched: act_tunnel_key: Don't dump dst port if it wasn't set

It's possible to set a tunnel without a destination port. However,
on dump(), a zero dst port is returned to user space even if it was not
set, fix that.

Note that so far it wasn't required, b/c key less tunnels were not
supported and the UDP tunnels do require destination port.

Signed-off-by: Adi Nissim <[email protected]>
Reviewed-by: Oz Shlomo <[email protected]>
Acked-by: Jiri Pirko <[email protected]>
Signed-off-by: David S. Miller <[email protected]>