OMAP3: use a single board file for IGEP devices

Even when the IGEPv2 board and the IGEP Computer-on-Module
are different from a form factor point of view, they are
very similar in the fact that share many components and how
they are wired.

So, it is possible (and better) to have a single board file
for both devices and just use the CONFIG_MACH_TYPE to make
a differentiation between each board when needed.

This change avoids code duplication by removing 298 lines of
code and makes future maintenance easier.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>