[media] v4l: vsp1: Store the memory format in struct vsp1_rwpf

Move the format from struct vsp1_video to struct vsp1_rwpf to prepare
for VSPD KMS support that will not instantiate V4L2 video device nodes.

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