media: dt-bindings: ti,ds90ub960: Add missing type for "i2c-alias"

Every DT property needs a type defined, but "i2c-alias" is missing any
type definition. It's a "uint32", so add a type reference.

Fixes: 313e8b32

 ("media: dt-bindings: media: add TI DS90UB960 FPD-Link III Deserializer")
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20231020170225.3632933-1-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>