ARM: LPC32xx: DTS adjustment for key matrix controller

This patch connects the lpc32xx-key driver to the LPC32xx platform (via
lpc32xx.dtsi), and more specifically to the reference board via its dts file.

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