arm64: dts: qcom: sc7180: add dedicated IMEM and syscon compatibles

Add proper compatibles to the IMEM device node:
1. syscon to allow accessing memory from other devices,
2. dedicated compatible as required for syscon and simple-mfd nodes.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220607171848.535128-10-krzysztof.kozlowski@linaro.org

arch/arm64/boot/dts/qcom/sc7180.dtsi

@@ -3243,7 +3243,7 @@ spmi_bus: spmi@c440000 {
 		};
 
 		sram@146aa000 {
-			compatible = "simple-mfd";
+			compatible = "qcom,sc7180-imem", "syscon", "simple-mfd";
 			reg = <0 0x146aa000 0 0x2000>;
 
 			#address-cells = <1>;