arm64: dts: qcom: msm8976: Use mboxes properties for APCS

Instead of passing the syscon to the various nodes, use the mbox
interface using the mboxes property.
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20240424-apcs-mboxes-v1-6-6556c47cb501@z3ntu.xyzSigned-off-by: Bjorn Andersson <andersson@kernel.org>

arch/arm64/boot/dts/qcom/msm8976.dtsi

@@ -243,7 +243,7 @@ rpm: remoteproc {
 
 		smd-edge {
 			interrupts = <GIC_SPI 168 IRQ_TYPE_EDGE_RISING>;
-			qcom,ipc = <&apcs 8 0>;
+			mboxes = <&apcs 0>;
 			qcom,smd-edge = <15>;
 
 			rpm_requests: rpm-requests {
@@ -367,7 +367,7 @@ tz-apps@8dd00000 {
 	smp2p-hexagon {
 		compatible = "qcom,smp2p";
 		interrupts = <GIC_SPI 291 IRQ_TYPE_EDGE_RISING>;
-		qcom,ipc = <&apcs 8 10>;
+		mboxes = <&apcs 10>;
 
 		qcom,local-pid = <0>;
 		qcom,remote-pid = <2>;
@@ -390,7 +390,7 @@ adsp_smp2p_in: slave-kernel {
 	smp2p-modem {
 		compatible = "qcom,smp2p";
 		interrupts = <GIC_SPI 27 IRQ_TYPE_EDGE_RISING>;
-		qcom,ipc = <&apcs 8 14>;
+		mboxes = <&apcs 14>;
 
 		qcom,local-pid = <0>;
 		qcom,remote-pid = <1>;
@@ -413,7 +413,7 @@ modem_smp2p_in: slave-kernel {
 	smp2p-wcnss {
 		compatible = "qcom,smp2p";
 		interrupts = <GIC_SPI 143 IRQ_TYPE_EDGE_RISING>;
-		qcom,ipc = <&apcs 8 18>;
+		mboxes = <&apcs 18>;
 
 		qcom,local-pid = <0>;
 		qcom,remote-pid = <4>;