V4L/DVB: mt9m111: Added indication that MT9M131 is supported by this driver

Added this info to Kconfig and mt9m111.c, some comment cleanup,
replaced 'mt9m11x'-statements by clarifications or driver name.
Driver is fully compatible to mt9m131 which has only additional functions
compared to mt9m111. Those aren't used anyway at the moment.

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