dt-bindings: clock: Make marvell,mmp2-clock a power controller

This is a binding for the MMP2 power management units. As such apart from
providing the clocks, they also manage the power islands.

Signed-off-by: Lubomir Rintel <[e-mail]>
Link: https://lkml.kernel.org/r/[e-mail]
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

Documentation/devicetree/bindings/clock/marvell,mmp2-clock.yaml

···
   '#reset-cells':
     const: 1
 
+  '#power-domain-cells':
+    const: 1
+
 required:
   - compatible
   - reg
   - reg-names
   - '#clock-cells'
   - '#reset-cells'
+  - '#power-domain-cells'
 
 additionalProperties: false
 
···
       reg-names = "mpmu", "apmu", "apbc";
       #clock-cells = <1>;
       #reset-cells = <1>;
+      #power-domain-cells = <1>;
     };