arm64: dts: qcom: msm8953: Use mboxes in smsm node

With the smsm bindings and driver finally supporting mboxes, switch to
that and stop using apcs as syscon.
Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20240619-smsm-mbox-dts-v1-4-268ab7eef779@lucaweiss.euSigned-off-by: Bjorn Andersson <andersson@kernel.org>

arch/arm64/boot/dts/qcom/msm8953.dtsi

@@ -411,8 +411,7 @@ smsm {
 		#address-cells = <1>;
 		#size-cells = <0>;
 
-		qcom,ipc-1 = <&apcs 8 13>;
-		qcom,ipc-3 = <&apcs 8 19>;
+		mboxes = <0>, <&apcs 13>, <0>, <&apcs 19>;
 
 		apps_smsm: apps@0 {
 			reg = <0>;