arm64: dts: qcom: sm8250: power up dispcc on sm8250 by MMCX regulator

Add regulator controlling MMCX power domain to be used by display clock
controller on SM8250.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20201203142105.841666-8-dmitry.baryshkov@linaro.orgSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

arch/arm64/boot/dts/qcom/sm8250.dtsi

@@ -216,6 +216,13 @@ memory@80000000 {
 		reg = <0x0 0x80000000 0x0 0x0>;
 	};
 
+	mmcx_reg: mmcx-reg {
+		compatible = "regulator-fixed-domain";
+		power-domains = <&rpmhpd SM8250_MMCX>;
+		required-opps = <&rpmhpd_opp_low_svs>;
+		regulator-name = "MMCX";
+	};
+
 	pmu {
 		compatible = "arm,armv8-pmuv3";
 		interrupts = <GIC_PPI 7 IRQ_TYPE_LEVEL_HIGH>;
@@ -2064,6 +2071,7 @@ opp-358000000 {
 		dispcc: clock-controller@af00000 {
 			compatible = "qcom,sm8250-dispcc";
 			reg = <0 0x0af00000 0 0x20000>;
+			mmcx-supply = <&mmcx_reg>;
 			clocks = <&rpmhcc RPMH_CXO_CLK>,
 				 <&dsi0_phy 0>,
 				 <&dsi0_phy 1>,