dt-bindings: leds: lp50xx: fix LED children names

The lp50xx LEDs expects to have single-color LED children with unit
addresses.  This is required by the driver and provided by existing
DTSes.  Fix the binding to match actual usage.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
[This depends on previous schema-fixing patch, so I deleted Fixes; we
don't want to deal with this in stable]
Signed-off-by: Pavel Machek <pavel@ucw.cz>

Documentation/devicetree/bindings/leds/leds-lp50xx.yaml

@@ -67,8 +67,14 @@ patternProperties:
           for the child node.  The LED modules can either be used stand alone
           or grouped into a module bank.
 
+      '#address-cells':
+        const: 1
+
+      '#size-cells':
+        const: 0
+
     patternProperties:
-      "(^led-[0-9a-f]$|led)":
+      "^led@[0-9a-f]+$":
         type: object
         $ref: common.yaml#