media: rkisp1: Fix memory leaks in rkisp1_isp_unregister()

Add missing call to v4l2_subdev_cleanup() to fix memory leak.

Link: https://lore.kernel.org/r/20231122-rkisp-fixes-v2-2-78bfb63cdcf8@ideasonboard.com



Fixes: 2cce0a36 ("media: rkisp1: isp: Use V4L2 subdev active state")
Reviewed-by: Tommaso Merciai <tomm.merciai@gmail.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>