Initial support for Nomadik 8815 development board

The NMDK8815 board is distributed by ST Microelectornics.
Other (proprietary) code must be run to unlock the CPU before
U-Boot runs. doc/README.nmdk8815 outlines the boot sequence.

This is the initial port, with basic infrastructure and
a working serial port.

Signed-off-by: Alessandro Rubini <rubini@unipv.it>
Acked-by: Andrea Gallo <andrea.gallo@stnwireless.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>