dt-bindings: memory: tegra210: Mark EMC as cooling device

The external memory controller found on Tegra210 can use throttling of
the EMC frequency in order to reduce the memory chip temperature. Mark
the memory controller as a cooling device to take advantage of this
functionality.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Author: thierryreding

Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.yaml

@@ -52,14 +52,17 @@ properties:
       Should contain freqs and voltages and opp-supported-hw property, which
       is a bitfield indicating SoC speedo ID mask.
 
+allOf:
+  - $ref: /schemas/thermal/thermal-cooling-devices.yaml
+
 required:
   - compatible
   - reg
   - clocks
   - clock-names
   - nvidia,memory-controller
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |
@@ -90,4 +93,5 @@ examples:
         operating-points-v2 = <&dvfs_opp_table>;
 
         #interconnect-cells = <0>;
+        #cooling-cells = <2>;
     };