media: rcar-vin: update bytesperline and sizeimage calculation

Remove over complicated logic to calculate the value for bytesperline
and sizeimage that was carried over from the soc_camera port. There is
no need to find the max value of bytesperline and sizeimage from
user-space as they are set to 0 before the max_t() operation.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>