Add sunxi_emac to /etc/modules so that eth0 shows up.

The sunxi_emac module doesn't appear to have modinfo/modalias set up, so it doesn't modprobe automagically, so we add it to /etc/modules in order to have an eth0 device on the cubieboard2.

Signed-off-by: Steev Klimaszewski (Kali Developer) <steev@kali.org>