media: dt-bindings: mediatek,vcodec-encoder: Drop assigned-clock properties

media: dt-bindings: mediatek,vcodec-encoder: Drop assigned-clock properties

The assigned-clock properties are always allowed on nodes with
'clocks' and generally not required. Additionally the mt8183 doesn't
define them, so they must not be required in that case.

Signed-off-by: "Rob Herring (Arm)" <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250317214621.794674-1-robh@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>