arm64: dts: msm8996: Transition smp2p and smd to mailbox

The smd and smp2p drivers now support accessing the APCS GLOBAL IPC
register through the mailbox framework, so migrate the msm8996 dts to
use this and remove the syscon based APCS node.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>

arch/arm64/boot/dts/qcom/msm8996.dtsi

@@ -407,11 +407,6 @@ intc: interrupt-controller@9bc0000 {
 			interrupts = <GIC_PPI 9 IRQ_TYPE_LEVEL_HIGH>;
 		};
 
-		apcs: syscon@9820000 {
-			compatible = "syscon";
-			reg = <0x9820000 0x1000>;
-		};
-
 		apcs_glb: mailbox@9820000 {
 			compatible = "qcom,msm8996-apcs-hmss-global";
 			reg = <0x9820000 0x1000>;
@@ -1138,7 +1133,7 @@ smd-edge {
 			interrupts = <GIC_SPI 156 IRQ_TYPE_EDGE_RISING>;
 
 			label = "lpass";
-			qcom,ipc = <&apcs 16 8>;
+			mboxes = <&apcs_glb 8>;
 			qcom,smd-edge = <1>;
 			qcom,remote-pid = <2>;
 		};
@@ -1150,7 +1145,7 @@ adsp-smp2p {
 
 		interrupts = <0 158 IRQ_TYPE_EDGE_RISING>;
 
-		qcom,ipc = <&apcs 16 10>;
+		mboxes = <&apcs_glb 10>;
 
 		qcom,local-pid = <0>;
 		qcom,remote-pid = <2>;
@@ -1174,7 +1169,7 @@ modem-smp2p {
 
 		interrupts = <GIC_SPI 451 IRQ_TYPE_EDGE_RISING>;
 
-		qcom,ipc = <&apcs 16 14>;
+		mboxes = <&apcs_glb 14>;
 
 		qcom,local-pid = <0>;
 		qcom,remote-pid = <1>;
@@ -1198,7 +1193,7 @@ smp2p-slpi {
 
 		interrupts = <GIC_SPI 178 IRQ_TYPE_EDGE_RISING>;
 
-		qcom,ipc = <&apcs 16 26>;
+		mboxes = <&apcs_glb 26>;
 
 		qcom,local-pid = <0>;
 		qcom,remote-pid = <3>;