ARM: dts: msm: Adding support to send messages to AOP using QMP transport

This is require to set Cap frequency of DDR based on SKU.

Change-Id: I7ed8906693c6fbe93f007bbaabe31906fe759cf1

bindings/arm/msm/aop-set-ddr.txt

@@ -0,0 +1,17 @@
+AOP set ddr interface:
+-----------------
+
+AOP set ddr is an interface to send data to the Always on
+processor using QMP.
+
+Required properties :
+- compatible : must be "qcom,aop-set-ddr-freq"
+- mboxes : list of QMP mailbox phandle and channel identifier tuples
+- mbox-names : names of the listed mboxes
+
+Example :
+       aop-set-ddr-freq {
+               compatible = "qcom,aop-set-ddr-freq";
+               mboxes = <&qmp_aop 0>;
+               mbox-names = "aop";
+       };