media: renesas: vsp1: Add support IIF ISP Interface

media: renesas: vsp1: Add support IIF ISP Interface

The IIF (ISP InterFace) is a VSP2 function that transfers data
to the ISP by reading from external memory through two RPF
instances.

Add support for it in the vsp1 driver by introducing a new entity
type. The sole required operation is to enable the IIF function
during configure_stream().

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Jacopo Mondi <jacopo.mondi+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/20250401-v4h-iif-v7-1-cc547c0bddd5@ideasonboard.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>