V4L/DVB (12529): soc-camera: switch to s_crop v4l2-subdev video operation

Remove set_crop soc-camera device method and switch to s_crop from v4l2-subdev
video operations. Also extend non-i2c drivers to also hold a pointer to their
v4l2-subdev instance in control device driver-data, i.e., in
dev_get_drvdata((struct device *)to_soc_camera_control(icd))

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