linux: add missing dependencies to kmod-ip6tables

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37389 3c298f89-4303-0410-b956-a3cf2f4a3e73
gen-dependencies.sh: sort kmod dependencies

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

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37390 3c298f89-4303-0410-b956-a3cf2f4a3e73