sfc: conntrack state matches in TC rules

Parse ct_state trk/est, mark and zone out of flower keys, and plumb
 them through to the hardware, performing some minor translations.
Nothing can actually hit them yet as we're not offloading any DO_CT
 actions.

Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@amd.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>