ARM: dts: am33xx: add PDU001 board

This patch adds support for the PDU001 board from EETS GmbH.
The board is built around the byteENGINE module AM335X from
bytes at work AG which in turn is built around a Sitara SoC
from TI.

Signed-off-by: Felix Brack <fb@ltec.ch>
Signed-off-by: Tony Lindgren <tony@atomide.com>