[NETFILTER]: nfnetlink_log: fix some constants

Fix timeout (one second is 1 * HZ) and convert max packet copy length
to #defined constant.

Signed-off-by: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>