arm64: dts: qcom: sc8180x: Hook up VDD_CX as GCC parent domain

Most of GCC is powered by the CX rail. Describe that relationship to
let the performance state requests trickle up the chain.

Fixes: 8575f197 ("arm64: dts: qcom: Introduce the SC8180x platform")
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20231230-topic-8180_more_fixes-v1-2-93b5c107ed43@linaro.orgSigned-off-by: Bjorn Andersson <andersson@kernel.org>

arch/arm64/boot/dts/qcom/sc8180x.dtsi

@@ -782,6 +782,7 @@ gcc: clock-controller@100000 {
 			clock-names = "bi_tcxo",
 				      "bi_tcxo_ao",
 				      "sleep_clk";
+			power-domains = <&rpmhpd SC8180X_CX>;
 		};
 
 		qupv3_id_0: geniqup@8c0000 {