dt-bindings: sram: sunxi-sram: Add D1 compatible string

D1 needs to export a register for managing some LDO regulators, so it
needs a unique compatible.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220815041248.53268-3-samuel@sholland.orgSigned-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>

Documentation/devicetree/bindings/sram/allwinner,sun4i-a10-system-control.yaml

@@ -33,6 +33,7 @@ properties:
           - allwinner,sun5i-a13-system-control
           - allwinner,sun8i-a23-system-control
           - allwinner,sun8i-h3-system-control
+          - allwinner,sun20i-d1-system-control
           - allwinner,sun50i-a64-system-control
           - allwinner,sun50i-h5-system-control
           - allwinner,sun50i-h616-system-control