uboot-phytec

arm: Remove IXP425 boards pdnb3 and scpu

Remove Prodrive pdnb3 board (including the scpu variant) support
from mainline. As its unmaintained and not needed any more for
quite some time.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Martijn de Gouw <martijn.de.gouw@prodrive.nl>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>