dt-bindings: media: renesas,vin: Add Gen4 family fallback

dt-bindings: media: renesas,vin: Add Gen4 family fallback

The Gen4 SoCs V3U, V4H and V4M have a similar video capture pipelines.

The datasheets for the SoCs have small nuances around the Pre-Clip
registers ELPrC and EPPrC in three use-cases, interlaced images,
embedded data and RAW8 input. On V4H the values written to the registers
are based on odd numbers while on V4M they are even numbers, values are
based on the input image size. No board that uses these SoCs which also
have the external peripherals to test these nuances exists. Most likely
this is an issue in the datasheet.

Before adding bindings for V4M add a family compatible fallback for
Gen4. That way the driver only needs to be updated once for Gen4, and we
still have the option to fix any problems in the driver if any testable
differences between the SoCs are found.

There are already DTS files using the V3U and V4H compatibles which need
to be updated to not produce a warning for DTS checks. The driver also
needs to keep the compatible values to be backward compatible , but for
new Gen4 SoCs such as V4M we can avoid this.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/20240704161620.1425409-2-niklas.soderlund+renesas@ragnatech.se
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>