ARM: dts: qcom: mdm9615: add missing reg in cpu@0 node

Fixes cpu@0: 'reg' is a required property from dtbs check.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220928-mdm9615-dt-schema-fixes-v4-3-dac2dfaac703@linaro.org

arch/arm/boot/dts/qcom-mdm9615.dtsi

@@ -27,6 +27,7 @@ cpus {
 
 		cpu0: cpu@0 {
 			compatible = "arm,cortex-a5";
+			reg = <0>;
 			device_type = "cpu";
 			next-level-cache = <&L2>;
 		};