configs: migrate ubispl boards to KConfig

Migrate the ubispl configuration for the omap3_igep00x0 and
am335x_igep003x boards to KConfig. Both boards were built with
SOURCE_DATE_EPOCH=0 and found to be equal before and after.

Signed-off-by: Markus Klotzbuecher <markus.klotzbuecher@kistler.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Javier Martínez Canillas <javier@dowhile0.org>
Cc: Enric Balletbo i Serra <eballetbo@gmail.com>
Acked-by: Enric Balletbo i Serra <eballetbo@gmail.com>