netfilter: xt_socket: use IP early demux

With IP early demux added in linux-3.6, we perform TCP lookup in IP
layer before iptables hooks.

We can avoid doing a second lookup in xt_socket.

Change-Id: I9a29233ab0acc40a528374910c010e383af3eaf3
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Git-commit: 00028aa37098168048728acc32ab0206687f2920
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[harouth@codeaurora.org: resolve trivial merge conflicts]
Signed-off-by: Harout Hedeshian <harouth@codeaurora.org>