ARM: OMAP3: Revamp IGEP module default configuration

The default IGEP configuration doesn't do anything useful; using some
boot.scr search logic like BeagleBoard is much more useful.

Signed-off-by: Enric Balletbo i Serra <eballetbo@iseebcn.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>