media: dt-bindings: mediatek,vcodec: Don't require assigned-clocks

On MT8183 it's not necessary to configure the parent for the clocks.
Remove the assigned-clocks and assigned-clock-parents from the required
list.

Signed-off-by: Nícolas F. R. A. Prado <[e-mail]>
Reviewed-by: Matthias Brugger <[e-mail]>
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

Documentation/devicetree/bindings/media/mediatek,vcodec-decoder.yaml

···
   - clocks
   - clock-names
   - iommus
-  - assigned-clocks
-  - assigned-clock-parents
 
 allOf:
   - if: