dt-bindings: net: sun4i-emac: add dma support

The sun4i EMAC supports DMA for data transmission,
so it is necessary to add DMA options to the device tree bindings.

Signed-off-by: Conley Lee <[e-mail]>
Acked-by: Rob Herring (Arm) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/devicetree/bindings/net/allwinner,sun4i-a10-emac.yaml

···
       - items:
           - description: phandle to SRAM
           - description: register value for device
+  dmas:
+    items:
+      - description: RX DMA Channel
+      - description: TX DMA Channel
+
+  dma-names:
+    items:
+      - const: rx
+      - const: tx
 
 required:
   - compatible