ARM: davinci: cp_intc: Add OF support for TI interrupt controller

Add a function to initialize the Common Platform Interrupt Controller
(cp_intc) from TI used on OMAP-L1x SoCs using a device tree node.

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: davinci-linux-open-source@linux.davincidsp.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Sergei Shtylyov <sshtylyov@mvista.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>