dt-bindings: mfd: syscon: Add compatibles for Loongson-1 syscon

Add Loongson LS1B and LS1C compatibles for system controller.

Signed-off-by: Keguang Zhang <keguang.zhang@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/mfd/syscon.yaml

@@ -49,6 +49,8 @@ properties:
               - hisilicon,peri-subctrl
               - hpe,gxp-sysreg
               - intel,lgm-syscon
+              - loongson,ls1b-syscon
+              - loongson,ls1c-syscon
               - marvell,armada-3700-usb2-host-misc
               - mediatek,mt8135-pctl-a-syscfg
               - mediatek,mt8135-pctl-b-syscfg