Merge branch 'consolidate-udp-ipv6-route-lookups'

Beniamino Galvani says:

====================
net: consolidate IPv6 route lookup for UDP tunnels

At the moment different UDP tunnels rely on different functions for
IPv6 route lookup, and those functions all implement the same
logic.

Extend the generic lookup function so that it is suitable for all UDP
tunnel implementations, and then adapt bareudp, geneve and vxlan to
use it.

This is similar to what already done for IPv4.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>