ARM: LPC32xx: Add dts for EA3250 reference board

There is another reference/development board for the LPC32xx SoC (besides the
Phytec 3250): The Embedded Artists LPC3250 board. This patch adds a default dts
file for it.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Acked-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>