dt-bindings: i2c: rk3x: add support for rv1108

Add dt Document for i2c controller on rv1108
Signed-off-by: NAndy Yan <andy.yan@rock-chips.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/i2c-rk3x.txt

@@ -7,6 +7,7 @@ Required properties :
 
  - reg : Offset and length of the register set for the device
  - compatible: should be one of the following:
+   - "rockchip,rv1108-i2c": for rv1108
    - "rockchip,rk3066-i2c": for rk3066
    - "rockchip,rk3188-i2c": for rk3188
    - "rockchip,rk3228-i2c": for rk3228