[NETFILTER] xt_policy.c: kill some bloat

net/netfilter/xt_policy.c:
  policy_mt | -906
 1 function changed, 906 bytes removed, diff: -906

net/netfilter/xt_policy.c:
  match_xfrm_state | +427
 1 function changed, 427 bytes added, diff: +427

net/netfilter/xt_policy.o:
 2 functions changed, 427 bytes added, 906 bytes removed, diff: -479

Alternatively, this could be done by combining identical
parts of the match_policy_in/out()

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>