media: rkisp1: resizer: Drop unneeded local variable

The sink_y local variable in rkisp1_rsz_config() stores a copy of the
sink_crop crop rectangle. Drop it, and rename sink_crop to sink_y.

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