kernel - PF SMP work - fix RDR rules

* Use the global state table for all global-flagged state.  RDR
  rules can apparently cause PF_SK_WIRE/PF_SK_STACK to be
  reversed so our global state table tests which only used
  PF_SK_WIRE for GLOBAL-flagged translations were not sufficient.

* Fixes issues with the reverse packet direction for a rdr
  rule not finding the reverse state.

* Note that RDR rules will not be SMP-optimal.

* Adds a bit more overhead for NAT translations which are not
  SMP optimal (however, most NAT translations select a port
  that will be SMP optimal).

Reported-by: alexh