arm64: dts: qcom: sc7280: Add the missing MDSS icc path

MDSS, aside from the MDP-MEM path, also requires the CPU-DISP_CFG one.
Failing to provide it may result in register accesses failing and that's
never good.

Add the missing path.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20231125-topic-rb1_feat-v3-7-4cbb567743bb@linaro.org


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