This baseboard is used on the handbot and eybot robots.

The sel gpios are used as enables and rst signals on smartbot, thus the
sel init is moved from mx31moboard file to board files.
Signed-off-by: NValentin Longchamp <valentin.longchamp@epfl.ch>
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>