datapath: Account for "udp: Do not require sock in udp_tunnel_xmit_skb"

datapath: Account for "udp: Do not require sock in udp_tunnel_xmit_skb"

Upstream commit:
    udp: Do not require sock in udp_tunnel_xmit_skb

    The UDP tunnel transmit functions udp_tunnel_xmit_skb and
    udp_tunnel6_xmit_skb include a socket argument. The socket being
    passed to the functions (from VXLAN) is a UDP created for receive
    side. The only thing that the socket is used for in the transmit
    functions is to get the setting for checksum (enabled or zero).
    This patch removes the argument and and adds a nocheck argument
    for checksum setting. This eliminates the unnecessary dependency
    on a UDP socket for UDP tunnel transmit.

    Signed-off-by: Tom Herbert <therbert@google.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
Upstream: d998f8ef ("udp: Do not require sock in udp_tunnel_xmit_skb")
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Thomas Graf <tgraf@noironetworks.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>