dt-bindings: net: oxnas-dwmac: remove obsolete bindings

Due to lack of maintenance and stall of development for a few years now,
and since no new features will ever be added upstream, remove the
OX810 and OX820 dwmac glue.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Daniel Golle <daniel@makrotopia.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/oxnas-dwmac.txt

-* Oxford Semiconductor OXNAS DWMAC Ethernet controller
-
-The device inherits all the properties of the dwmac/stmmac devices
-described in the file stmmac.txt in the current directory with the
-following changes.
-
-Required properties on all platforms:
-
-- compatible:	For the OX820 SoC, it should be :
-		- "oxsemi,ox820-dwmac" to select glue
-		- "snps,dwmac-3.512" to select IP version.
-		For the OX810SE SoC, it should be :
-		- "oxsemi,ox810se-dwmac" to select glue
-		- "snps,dwmac-3.512" to select IP version.
-
-- clocks: Should contain phandles to the following clocks
-- clock-names:	Should contain the following:
-		- "stmmaceth" for the host clock - see stmmac.txt
-		- "gmac" for the peripheral gate clock
-
-- oxsemi,sys-ctrl: a phandle to the system controller syscon node
-
-Example :
-
-etha: ethernet@40400000 {
-	compatible = "oxsemi,ox820-dwmac", "snps,dwmac-3.512";
-	reg = <0x40400000 0x2000>;
-	interrupts = <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,
-		     <GIC_SPI 17 IRQ_TYPE_LEVEL_HIGH>;
-	interrupt-names = "macirq", "eth_wake_irq";
-	mac-address = [000000000000]; /* Filled in by U-Boot */
-	phy-mode = "rgmii";
-
-	clocks = <&stdclk CLK_820_ETHA>, <&gmacclk>;
-	clock-names = "gmac", "stmmaceth";
-	resets = <&reset RESET_MAC>;
-
-	/* Regmap for sys registers */
-	oxsemi,sys-ctrl = <&sys>;
-
-};