Broadcom IPROC USB Device controller.

The device node is used for UDCs integrated into Broadcom's
iProc family (Northstar2, Cygnus) of SoCs'. The UDC is based
on Synopsys Designware Cores AHB Subsystem Device Controller
IP.

Required properties:
 - compatible: Add the compatibility strings for supported platforms.
   For Broadcom NS2 platform, add "brcm,ns2-udc","brcm,iproc-udc".
   For Broadcom Cygnus platform, add "brcm,cygnus-udc", "brcm,iproc-udc".
 - reg: Offset and length of UDC register set
 - interrupts: description of interrupt line
 - phys: phandle to phy node.

Example:
	udc_dwc: usb@664e0000 {
		compatible = "brcm,ns2-udc", "brcm,iproc-udc";
		reg = <0x664e0000 0x2000>;
		interrupts = <GIC_SPI 424 IRQ_TYPE_LEVEL_HIGH>;
		phys = <&usbdrd_phy>;
