sh_eth: Add R7S9210 support

Add support for the R7S9210 which is part of the RZ/A2 series.

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/sh_eth.txt

@@ -16,6 +16,7 @@ Required properties:
 	      "renesas,ether-r8a7794"  if the device is a part of R8A7794 SoC.
 	      "renesas,gether-r8a77980" if the device is a part of R8A77980 SoC.
 	      "renesas,ether-r7s72100" if the device is a part of R7S72100 SoC.
+	      "renesas,ether-r7s9210" if the device is a part of R7S9210 SoC.
 	      "renesas,rcar-gen1-ether" for a generic R-Car Gen1 device.
 	      "renesas,rcar-gen2-ether" for a generic R-Car Gen2 or RZ/G1
 	                                device.