[PATCH] Add QE device tree definition

[Li Yang-r58472]

> > +   3) USB (Universal Serial Bus Controller)
> > +
> > +   Required properties:
> > +   - device_type : should be "usb".
> > +   - compatible : could be "qe_udc" or "fhci-hcd".
> > +   - model : the could be "host" or "slave".
> 
> got a 'l' on mode, if we are slave should we provide more info about
> what kinda slave we are (ie, what gadget driver should apply).

In current implementation of gadget, gadget driver is selected in kernel config and module loading.  Different gadget drivers can't be loaded at the same time for now.  Thus, having it in device tree will have no actual use.
> 
> > +   - reg : there will be two tuples of "address size".  The first
> > tuple is
> > +     offset and length of the device registers respectively; the
> > second is
> > +     offset and length of the device parameter RAM respectively.
> > +   - interrupts : <a b> where a is the interrupt number and b is a
> > +     field that represents an encoding of the sense and level
> > +     information for the interrupt.  This should be encoded based on
> > +     the information in section 2) depending on the type of interrupt
> > +     controller you have.
> > +   - interrupt-parent : the phandle for the interrupt controller that
> > +     services interrupts for this device.