dt-bindings: msm/dsi: Don't require vcca-supply on 14nm PHY

On some SoCs (hello SM6115) vcca-supply is not wired to any smd-rpm
or rpmh regulator, but instead powered by the VDD_MX line, which is
voted for in the DSI ctrl node.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Fixes: 8fc939e7

 ("dt-bindings: msm: dsi: add yaml schemas for DSI PHY bindings")
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/513555/
Link: https://lore.kernel.org/r/20221130135807.45028-1-konrad.dybcio@linaro.org


Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>