arm64: dts: renesas: r8a779g0: Add ISP core function block

arm64: dts: renesas: r8a779g0: Add ISP core function block

All ISP instances on V4H have both a channel select and core function
block, describe the core region in addition to the existing cs region.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20250423163113.2961049-4-niklas.soderlund+renesas@ragnatech.se
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>