dt-bindings: ata: rockchip-dwc-ahci: add missing power-domains

The Rockchip variant of the dwc-ahci controller does have and need power-
domains to work, though the binding does not mention them, making dtccheck
quite unhappy:

  DTC_CHK arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dtb
/home/devel/hstuebner/00_git-repos/linux-rockchip/_build-arm64/arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dtb: sata@fc800000: Unevaluated properties are not allowed ('power-domains' was unexpected)
        from schema $id: http://devicetree.org/schemas/ata/rockchip,dwc-ahci.yaml#

Fix that by adding the missing power-domain property to the binding.

Fixes: 85b0e13b ("dt-bindings: ata: dwc-ahci: add Rockchip RK3588")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

Documentation/devicetree/bindings/ata/rockchip,dwc-ahci.yaml

@@ -35,6 +35,9 @@ properties:
   ports-implemented:
     const: 1
 
+  power-domains:
+    maxItems: 1
+
   sata-port@0:
     $ref: /schemas/ata/snps,dwc-ahci-common.yaml#/$defs/dwc-ahci-port