arm64: dts: qcom: sdm845: add missing power-controller compatible

dt-schema expect to have fallback compatible, which is now in-place.

Fixes warning generated by `make qcom/sdm845-oneplus-fajita.dtb`:
arch/arm64/boot/dts/qcom/sdm845-oneplus-fajita.dt.yaml: power-controller@c300000: compatible: ['qcom,sdm845-aoss-qmp'] is too short
        From schema: Documentation/devicetree/bindings/soc/qcom/qcom,aoss-qmp.yaml
Signed-off-by: David Heidelberg <david@ixit.cz>
Komu: David Heidelberg <david@ixit.cz>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211220211443.106754-1-david@ixit.cz

arch/arm64/boot/dts/qcom/sdm845.dtsi

@@ -4619,7 +4619,7 @@ aoss_reset: reset-controller@c2a0000 {
 		};
 
 		aoss_qmp: power-controller@c300000 {
-			compatible = "qcom,sdm845-aoss-qmp";
+			compatible = "qcom,sdm845-aoss-qmp", "qcom,aoss-qmp";
 			reg = <0 0x0c300000 0 0x100000>;
 			interrupts = <GIC_SPI 389 IRQ_TYPE_EDGE_RISING>;
 			mboxes = <&apss_shared 0>;