commit 504f85c9 upstream.

act_nat: use stack variable

structure tc_nat isn't too big for stack, so we can put it in stack.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Cc: dann frazier <dannf@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>