[media] mt9m111: move lastpage to struct mt9m111 for multi instances

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>