dt-bindings: net: Add bindings for National Instruments XGE netdev

This adds bindings for the NI XGE 1G/10G network device.
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NMoritz Fischer <mdf@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/nixge.txt

+* NI XGE Ethernet controller
+
+Required properties:
+- compatible: Should be "ni,xge-enet-2.00"
+- reg: Address and length of the register set for the device
+- interrupts: Should contain tx and rx interrupt
+- interrupt-names: Should be "rx" and "tx"
+- phy-mode: See ethernet.txt file in the same directory.
+- phy-handle: See ethernet.txt file in the same directory.
+- nvmem-cells: Phandle of nvmem cell containing the MAC address
+- nvmem-cell-names: Should be "address"
+
+Examples (10G generic PHY):
+	nixge0: ethernet@40000000 {
+		compatible = "ni,xge-enet-2.00";
+		reg = <0x40000000 0x6000>;
+
+		nvmem-cells = <&eth1_addr>;
+		nvmem-cell-names = "address";
+
+		interrupts = <0 29 IRQ_TYPE_LEVEL_HIGH>, <0 30 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-names = "rx", "tx";
+		interrupt-parent = <&intc>;
+
+		phy-mode = "xgmii";
+		phy-handle = <&ethernet_phy1>;
+
+		ethernet_phy1: ethernet-phy@4 {
+			compatible = "ethernet-phy-ieee802.3-c45";
+			reg = <4>;
+		};
+	};