media: vsp1: Add VSPX support

media: vsp1: Add VSPX support

Add support for VSPX, a specialized version of the VSP2 that
transfers data to the ISP. The VSPX is composed of two RPF units
to read data from external memory and an IIF instance that performs
transfer towards the ISP.

The VSPX is supported through a newly introduced vsp1_vspx.c file that
exposes two interfaces: vsp1_vspx interface, declared in vsp1_vspx.h
for the vsp1 core to initialize and cleanup the VSPX, and a vsp1_isp
interface, declared in include/media/vsp1.h for the ISP driver to
control the VSPX operations.

Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/20250617-b4-vspx-v13-1-9f4054c1c9af@ideasonboard.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>