media: dt-bindings: media: renesas,csi2: Update data-lanes property

CSI-2 (CSI4LNK0) on R-Car and RZ/G2 supports 4-lane mode which is already
handled by rcar-csi2.c driver. This patch updates the data-lanes property
to describe the same.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>