dt-bindings: dwmac: Add bindings for new Loongson SoC and bridge chip

Add the dwmac bindings for the Loongson-2K SoC and the LS7A
bridge chip.
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/snps,dwmac.yaml

@@ -51,11 +51,15 @@ properties:
         - allwinner,sun8i-r40-emac
         - allwinner,sun8i-v3s-emac
         - allwinner,sun50i-a64-emac
+        - loongson,ls2k-dwmac
+        - loongson,ls7a-dwmac
         - amlogic,meson6-dwmac
         - amlogic,meson8b-dwmac
         - amlogic,meson8m2-dwmac
         - amlogic,meson-gxbb-dwmac
         - amlogic,meson-axg-dwmac
+        - loongson,ls2k-dwmac
+        - loongson,ls7a-dwmac
         - ingenic,jz4775-mac
         - ingenic,x1000-mac
         - ingenic,x1600-mac
@@ -363,6 +367,8 @@ allOf:
               - allwinner,sun8i-r40-emac
               - allwinner,sun8i-v3s-emac
               - allwinner,sun50i-a64-emac
+              - loongson,ls2k-dwmac
+              - loongson,ls7a-dwmac
               - ingenic,jz4775-mac
               - ingenic,x1000-mac
               - ingenic,x1600-mac