dt-bindings: net: ave: add PXs3 support

Add a compatible string for ethernet controller on UniPhier PXs3 SoC.
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/socionext,uniphier-ave4.txt

@@ -9,6 +9,7 @@ Required properties:
 	- "socionext,uniphier-pxs2-ave4" : for PXs2 SoC
 	- "socionext,uniphier-ld11-ave4" : for LD11 SoC
 	- "socionext,uniphier-ld20-ave4" : for LD20 SoC
+	- "socionext,uniphier-pxs3-ave4" : for PXs3 SoC
  - reg: Address where registers are mapped and size of region.
  - interrupts: Should contain the MAC interrupt.
  - phy-mode: See ethernet.txt in the same directory. Allow to choose