kernel: netfilter.mk: Explicitly set the order of autoloaded modules

In my machine, the file is created with arptable_filter before
arp_tables. This can't happen because the former depends on the
latter.

So, instead of rely on wildcards (*.ko), set by hand the files to
be loaded in the correct order.

Signed-off-by: Jonh Wendell <jonh.wendell@oiwifi.com.br>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36512 3c298f89-4303-0410-b956-a3cf2f4a3e73