usb: host: add DT bindings for faraday fotg2

This adds device tree bindings for the Faraday FOTG2
dual-mode host controller.

Cc: devicetree@vger.kernel.org
Signed-off-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/faraday,fotg210.txt

+Faraday FOTG Host controller
+
+This OTG-capable USB host controller is found in Cortina Systems
+Gemini and other SoC products.
+
+Required properties:
+- compatible: should be one of:
+  "faraday,fotg210"
+  "cortina,gemini-usb", "faraday,fotg210"
+- reg: should contain one register range i.e. start and length
+- interrupts: description of the interrupt line
+
+Optional properties:
+- clocks: should contain the IP block clock
+- clock-names: should be "PCLK" for the IP block clock
+
+Required properties for "cortina,gemini-usb" compatible:
+- syscon: a phandle to the system controller to access PHY registers
+
+Optional properties for "cortina,gemini-usb" compatible:
+- cortina,gemini-mini-b: boolean property that indicates that a Mini-B
+  OTG connector is in use
+- wakeup-source: see power/wakeup-source.txt
+
+Example for Gemini:
+
+usb@68000000 {
+	compatible = "cortina,gemini-usb", "faraday,fotg210";
+	reg = <0x68000000 0x1000>;
+	interrupts = <10 IRQ_TYPE_LEVEL_HIGH>;
+	clocks = <&cc 12>;
+	clock-names = "PCLK";
+	syscon = <&syscon>;
+	wakeup-source;
+};