omap3: Add minimal IGEP v2 support

The IGEP v2 board is a low-cost, fan-less and industrial temperature
range single board computer that unleashes laptop-like performance and
expandability without the bulk, expense, or noise of typical desktop
machines. Its architecture shares much in common with other OMAP3 boards.

Signed-off-by: Enric Balletbo i Serra <eballetbo@iseebcn.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>