Merge branch 'ila-precompute'

Tom Herbert says:

====================
ila: Precompute checksums

This patch set:
 - Adds argument ot LWT build_state that holds a pointer to the fib
   configuration being applied to the new route
 - Adds support in ILA to precompute checksum difference for
   performance optimization

v2:
 - Move return argument in build_state to end of arguments

v3:
 - Update the signature for ip6_tun_build_state()
====================

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