dt-bindings: usb: dwc3: remove old DWC3 wrapper

There is now an updated bindings for these SoCs making the old
compatible obsolete.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

Documentation/devicetree/bindings/usb/amlogic,dwc3.txt

@@ -1,42 +0,0 @@
-Amlogic Meson GX DWC3 USB SoC controller
-
-Required properties:
-- compatible:	depending on the SoC this should contain one of:
-			* amlogic,meson-axg-dwc3
-			* amlogic,meson-gxl-dwc3
-- clocks:	a handle for the "USB general" clock
-- clock-names:	must be "usb_general"
-- resets:	a handle for the shared "USB OTG" reset line
-- reset-names:	must be "usb_otg"
-
-Required child node:
-A child node must exist to represent the core DWC3 IP block. The name of
-the node is not important. The content of the node is defined in dwc3.txt.
-
-PHY documentation is provided in the following places:
-- Documentation/devicetree/bindings/phy/meson-gxl-usb2-phy.txt
-- Documentation/devicetree/bindings/phy/meson-gxl-usb3-phy.txt
-
-Example device nodes:
-		usb0: usb@ff500000 {
-			compatible = "amlogic,meson-axg-dwc3";
-			#address-cells = <2>;
-			#size-cells = <2>;
-			ranges;
-
-			clocks = <&clkc CLKID_USB>;
-			clock-names = "usb_general";
-			resets = <&reset RESET_USB_OTG>;
-			reset-names = "usb_otg";
-
-			dwc3: dwc3@ff500000 {
-				compatible = "snps,dwc3";
-				reg = <0x0 0xff500000 0x0 0x100000>;
-				interrupts = <GIC_SPI 30 IRQ_TYPE_LEVEL_HIGH>;
-				dr_mode = "host";
-				maximum-speed = "high-speed";
-				snps,dis_u2_susphy_quirk;
-				phys = <&usb3_phy>, <&usb2_phy0>;
-				phy-names = "usb2-phy", "usb3-phy";
-			};
-		};