dt-bindings: display: ingenic,jz4780-hdmi: Add missing clock-names

The binding references synopsys,dw-hdmi.yaml schema which defines both
'clocks' and 'clock-names' with variable length, therefore we need here
also same constraint for 'clock-names' as for 'clocks'.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250820-dt-bindings-display-v2-1-91e2ccba3d4e@linaro.org


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>