arm64: dts: qcom: msm8994: Add MMCC node

Describe the Multimedia Clock Controller block in the DT.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220319174645.340379-6-konrad.dybcio@somainline.org