ARMV7: OMAP3: Add support for Comelit DIG297 board

Board support for the DIG297 board manufactured by Comelit Group SpA.
It is a custom board based on the BeagleBoard <http://beagleboard.org/

> by
Texas Instruments.

The board support is based on the BeagleBoard implementation.

Signed-off-by: Luca Ceresoli <luca.ceresoli@comelit.it>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Albert Aribaud <albert.aribaud@free.fr>
Cc: Sandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>