Merge branch 'iptunnel-policy-based-routing'

Craig Gallek says:

====================
ip_tunnel: Allow policy-based routing through tunnels

iproute2 changes to follow.  Example usage:
  ip link add gre-test type gre local 10.0.0.1 remote 10.0.0.2 fwmark 0x4
  ip -detail link show gre-test
  ...
  ip link set gre-test type gre fwmark 0
====================

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