igep00x0: default to OMAP-specific serial driver

An OMAP specific serial driver was merged on the Linux kenel a long
time ago. So, it makes sense to default the console name to OMAP
ttyO instead of the generic ttyS naming.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
Acked-by: Enric Balletbo i Serra <eballetbo@gmail.com>