media: i2c: imx219: Calculate crop rectangle dynamically

Calculate the crop rectangle size and location dynamically when setting
the format, instead of storing it in the imx219_mode structure. This
removes duplicated information from the mode, to guarantee consistency.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>