ARM: dts: am335x: Add support for Bosch Guardian

The Bosch Guardian is a TI am335x based device.

It's hardware specifications are as follows:

 * 256 MB DDR3 memory
 * 512 MB NAND Flash
 * USB OTG
 * RS232
 * MicroSD external storage
 * LCD Display interface

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>
[tony@atomide.com: updated to use #include]
Signed-off-by: Tony Lindgren <tony@atomide.com>