media: renesas: vsp1: Initialize control handler after subdev

Some VSP modules initialize their control handler after initializing the
subdev, while some initialize it before. This makes the code
inconsistent and more error prone. Standardize on control initialization
after initializing the subdev.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi+renesas@ideasonboard.com>