arm64: dts: qcom: sc8180x: Require LOW_SVS vote for MMCX if DISPCC is on

To ensure the PLLs are getting enough power, cast a vote with DISPCC so
that MMCX is at least at LOW_SVS.

Fixes: 494dec9b ("arm64: dts: qcom: sc8180x: Add display and gpu nodes")
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20231230-topic-8180_more_fixes-v1-7-93b5c107ed43@linaro.org


Signed-off-by: Bjorn Andersson <andersson@kernel.org>