net/dst: Add dst port to dst_metadata utility functions

Add dst port parameter to __ip_tun_set_dst and __ipv6_tun_set_dst
utility functions.

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>