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: 313e8b32c616 ("media: dt-bindings: media: add TI DS90UB960 FPD-Link III Deserializer")
Reviewed-by: Laurent Pinchart <[e-mail]>
Acked-by: Conor Dooley <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Herring <[e-mail]>

Documentation/devicetree/bindings/media/i2c/ti,ds90ub960.yaml

···
             maxItems: 1
 
           i2c-alias:
+            $ref: /schemas/types.yaml#/definitions/uint32
             description:
               The I2C address used for the serializer. Transactions to this
               address on the I2C bus where the deserializer resides are