MXC: mach_armadillo5x0: Add USB Host support.

This add USB Host capability. The Armadillo 500 board is supplied
with two USB Host connectors driven by the USB OTG and USB Host 2
ports, through two NXP isp 1504 transceivers.

Signed-off-by: Alberto Panizzo <maramaopercheseimorto@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>