datapath: compat: Use dst-cache for Geneve and VxLAN tunnels.

datapath: compat: Use dst-cache for Geneve and VxLAN tunnels.

It partialy backport commit:
    commit d71785ffc7e7cae3fbdc4ea8a9d05b7a1c59f7b8
    Author: Paolo Abeni <pabeni@redhat.com>

    net: add dst_cache to ovs vxlan lwtunnel

    In case of UDP traffic with datagram length
    below MTU this give about 2% performance increase
    when tunneling over ipv4 and about 60% when tunneling
    over ipv6

    Signed-off-by: Paolo Abeni <pabeni@redhat.com>
    Suggested-and-acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
    Signed-off-by: David S. Miller <davem@davemloft.net>
Bug fix commit db3c6139e6e ("bpf, vxlan, geneve, gre: fix usage of
dst_cache on xmit"). is also included. Geneve changes
were added in 468dfffcd762cbb2777ec5a76bc21e3748ebf47e ("geneve: add
dst caching support")

Signed-off-by: Pravin B Shelar <pshelar@ovn.org>
Acked-by: Jesse Gross <jesse@kernel.org>