[media] v4l: vsp1: Don't create LIF entity when the userspace API is enabled

The LIF is only used when feeding the VSP output to the DU. The only way
to do so is by controlling the VSP directly from the DU driver and
disabling the VSP userspace API. There is thus no need to create a LIF
entity when the userspace API is enabled, as it can't be used in that
case.

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