datapath: Account for "udp: Add udp_sock_create for UDP tunnels to open listener...

datapath: Account for "udp: Add udp_sock_create for UDP tunnels to open listener socket"

Upstream commit:
    udp: Add udp_sock_create for UDP tunnels to open listener socket

    Added udp_tunnel.c which can contain some common functions for UDP
    tunnels. The first function in this is udp_sock_create which is used
    to open the listener port for a UDP tunnel.

    Signed-off-by: Tom Herbert <therbert@google.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
Upstream: 8024e028 ("udp: Add udp_sock_create for UDP tunnels to open listener socket")
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Thomas Graf <tgraf@noironetworks.com>