[media] mt9m111: changed MIN_DARK_COLS to MT9M131 spec count

Signed-off-by: Philipp Wiesner <p.wiesner@phytec.de>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>