arm/dts: Add support for OMAP4 SDP board

Add the SDP/Blaze (Software Development Board) support with
device tree.
That file is based on the omap4-panda.dts.

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