dt-bindings: leds: mt6370: Fix MT6370 LED indicator DT warning

Add '$ref' and 'unevaluatedProperties: false' in 'multi-led', and remove
unused 'allOf' property.

Fixes: 440c57da ("dt-bindings: leds: mt6370: Add MediaTek MT6370 current sink type LED indicator")
Signed-off-by: ChiaEn Wu <chiaen_wu@richtek.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/435f6888ebc20c5abae63eb9cb3a055b60db2ed1.1665050503.git.chiaen_wu@richtek.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/leds/mediatek,mt6370-indicator.yaml

@@ -13,9 +13,6 @@ description: |
   This module is part of the MT6370 MFD device.
   Add MT6370 LED driver include 4-channel RGB LED support Register/PWM/Breath Mode
 
-allOf:
-  - $ref: leds-class-multicolor.yaml#
-
 properties:
   compatible:
     const: mediatek,mt6370-indicator
@@ -29,6 +26,8 @@ properties:
 patternProperties:
   "^multi-led@[0-3]$":
     type: object
+    $ref: leds-class-multicolor.yaml#
+    unevaluatedProperties: false
 
     properties:
       reg: