netfilter: xt_conntrack: support matching on port ranges

Add a new revision 3 that contains port ranges for all of origsrc,
origdst, replsrc and repldst. The high ports are appended to the
original v2 data structure to allow sharing most of the code with
v1 and v2. Use of the revision specific port matching function is
made dependant on par->match->revision.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>