dt-bindings: display: bridge: nwl-dsi: Add common properties

Add common properties appearing in DTSes (assigned-clocks and others) to
fix dtbs_check warnings like:

  arch/arm64/boot/dts/freescale/imx8mq-evk.dt.yaml: mipi-dsi@30a00000:
    'assigned-clock-parents', 'assigned-clock-rates', 'assigned-clocks' do not match any of the regexes: '^panel@[0-9]+$', 'pinctrl-[0-9]+'

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200904145312.10960-3-krzk@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/display/bridge/nwl-dsi.yaml

@@ -30,6 +30,10 @@ properties:
   '#size-cells':
     const: 0
 
+  assigned-clock-parents: true
+  assigned-clock-rates: true
+  assigned-clocks: true
+
   clocks:
     items:
       - description: DSI core clock