[media] v4l: vsp1: Move video operations to vsp1_rwpf

This removes the dependency of vsp1_rpf and vsp1_wpf on vsp1_video,
making it possible to reuse the operations without a V4L2 video device
node.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>