[media] V4L: mt9t112: fix broken cropping and scaling

G_CROP, S_CROP, CROPCAP, G_FMT, and S_FMT functionality in the mt9t112
driver was broken on many occasions. This patch allows consistent
cropping for rectangles also larger than VGA and cleans up multiple
other issues in this area. It still doesn't add support for proper
scaling, using the sensor own scaler, so input window is still
always equal to the output frame.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>