dt-bindings: soc: qcom: stats: Add QMP handle

The stats can be expanded by poking the Always-On Subsystem through QMP.
Allow passing a QMP handle for configurations that support it.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231130-topic-ddr_sleep_stats-v1-1-5981c2e764b6@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Documentation/devicetree/bindings/soc/qcom/qcom-stats.yaml

@@ -31,10 +31,24 @@ properties:
   reg:
     maxItems: 1
 
+  qcom,qmp:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: Reference to the AOSS side-channel message RAM
+
 required:
   - compatible
   - reg
 
+allOf:
+  - if:
+      not:
+        properties:
+          compatible:
+            const: qcom,rpmh-stats
+    then:
+      properties:
+        qcom,qmp: false
+
 additionalProperties: false
 
 examples: