kernel: add a patch to make netfilter conntrack cache routing information

Significantly improves routing / NAT performance

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@43587 3c298f89-4303-0410-b956-a3cf2f4a3e73