media: dt-bindings: Make sure items in data-lanes are unique

The data-lanes property maps the logical lane numbers to the physical
lane numbers. The position of an entry is the logical lane number and
its value is the physical lane number. Since one physical lane can only
map to one logical lane, no number in the list should repeat. Add the
uniqueItems constraint on the property to enforce this.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Signed-off-by: Vaishnav Achath <vaishnav.a@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rob Herring <robh@kernel.org>