arm/dts: Add support for TI OMAP3 EVM board

Add OMAP3 EVM (OMAP3530, AM/DM37x) DTS file to use the omap3.dtsi SoC file,
along with memory node information.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>