powerpc/4xx: Sam440ep support

The Sam440ep is an high customizable general purpose mini-itx board,
based on the AMCC 440EP and with a LatticeXP FPGA onboard.

It's poduced by ACube Systems Srl (Bassano del Grappa, Italy),
http://www.acube-systems.biz

.

Signed-off-by: Giuseppe Coviello <gicoviello@gmail.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>