dt-bindings: backlight: lm3630a: Add enable-gpios to describe HWEN pin

Provide DT documentation for enable-gpios.
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml

@@ -29,6 +29,10 @@ properties:
   '#size-cells':
     const: 0
 
+  enable-gpios:
+    description: GPIO to use to enable/disable the backlight (HWEN pin).
+    maxItems: 1
+
 required:
   - compatible
   - reg
@@ -96,6 +100,7 @@ examples:
         led-controller@38 {
                 compatible = "ti,lm3630a";
                 reg = <0x38>;
+                enable-gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>;
 
                 #address-cells = <1>;
                 #size-cells = <0>;