Merge branch 'nfp-ipv6-tunnel'

John Hurley says:

====================
Add ipv6 tunnel support to NFP

The following patches add support for IPv6 tunnel offload to the NFP
driver.

Patches 1-2 do some code tidy up and prepare existing code for reuse in
IPv6 tunnels.
Patches 3-4 handle IPv6 tunnel decap (match) rules.
Patches 5-8 handle encap (action) rules.
Patch 9 adds IPv6 support to the merge and pre-tunnel rule functions.

v1->v2:
- fix compiler warning when building without CONFIG_IPV6 set -
  Jakub Kicinski (patch 7)
====================

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