media: dt-bindings: media: renesas,fcp: Allow three clocks for RZ/V2N SoC

Update the FCP DT schema to permit three clock inputs for the RZ/V2N SoC.
The FCP block on this SoC requires three separate clocks, unlike other
variants which use only one.

Fixes: f42eddf44fbf ("media: dt-bindings: media: renesas,fcp: Document RZ/V2N SoC")
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20251103194554.54313-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>