arm/dts: Add initial device tree support for OMAP3 SoC

Add initial OMAP3 soc file with empty ocp bus.

Based on initial patch from Manju:
http://www.spinics.net/lists/linux-omap/msg55830.html

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: G, Manjunath Kondaiah <manjugk@ti.com>