mx31moboard: setup all pins (v2)

As suggested by Sascha, here we setup all the pins that we are using in
the current (and currently reviewed) drivers for mx31moboard system.

changes since v1: changed I2C1 pin names

Signed-off-by: Valentin Longchamp <valentin.longchamp@epfl.ch>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>