igep00x0: Switch to use the generic distro configuration and environment.

This patch changes a little bit the environment, current environment was broken
for a long time, and board don't as expected sometimes, on production systems
this is fixed adding boot script. I think it's time to change this to make a
system conformant environment and use generic distro configurations and
environment instead. We can use a boot script for the old way boot mode.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>