media: v4l: vsp1: Share the CLU, LIF and LUT set_fmt pad operation code

The implementation of the set_fmt pad operation is identical in the
three modules. Move it to a generic helper function.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>