dt-bindings: net: dwmac: Fix typo in the R40 compatible

Even though both the driver and the device trees all use the
allwinner,sun8i-r40-gmac compatible, we documented the compatible as
allwinner,sun8i-r40-emac in the binding. Let's fix this.

Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Jose Abreu <joabreu@synopsys.com>
Cc: netdev@vger.kernel.org
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210924072756.869731-3-maxime@cerno.tech

Documentation/devicetree/bindings/net/allwinner,sun8i-a83t-emac.yaml

@@ -15,7 +15,7 @@ properties:
     oneOf:
       - const: allwinner,sun8i-a83t-emac
       - const: allwinner,sun8i-h3-emac
-      - const: allwinner,sun8i-r40-emac
+      - const: allwinner,sun8i-r40-gmac
       - const: allwinner,sun8i-v3s-emac
       - const: allwinner,sun50i-a64-emac
       - items:
@@ -91,7 +91,7 @@ allOf:
         compatible:
           contains:
             enum:
-              - allwinner,sun8i-r40-emac
+              - allwinner,sun8i-r40-gmac
 
     then:
       properties:

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

@@ -49,7 +49,7 @@ properties:
         - allwinner,sun7i-a20-gmac
         - allwinner,sun8i-a83t-emac
         - allwinner,sun8i-h3-emac
-        - allwinner,sun8i-r40-emac
+        - allwinner,sun8i-r40-gmac
         - allwinner,sun8i-v3s-emac
         - allwinner,sun50i-a64-emac
         - loongson,ls2k-dwmac
@@ -316,7 +316,7 @@ allOf:
               - allwinner,sun7i-a20-gmac
               - allwinner,sun8i-a83t-emac
               - allwinner,sun8i-h3-emac
-              - allwinner,sun8i-r40-emac
+              - allwinner,sun8i-r40-gmac
               - allwinner,sun8i-v3s-emac
               - allwinner,sun50i-a64-emac
               - ingenic,jz4775-mac
@@ -364,7 +364,7 @@ allOf:
               - allwinner,sun7i-a20-gmac
               - allwinner,sun8i-a83t-emac
               - allwinner,sun8i-h3-emac
-              - allwinner,sun8i-r40-emac
+              - allwinner,sun8i-r40-gmac
               - allwinner,sun8i-v3s-emac
               - allwinner,sun50i-a64-emac
               - loongson,ls2k-dwmac