* Xen hypervisor device tree bindings

Xen ARM virtual platforms shall have a top-level "hypervisor" node with
the following properties:

- compatible:
	compatible = "xen,xen-<version>", "xen,xen";
  where <version> is the version of the Xen ABI of the platform.

- reg: specifies the base physical address and size of a region in
  memory where the grant table should be mapped to, using an
  HYPERVISOR_memory_op hypercall. The memory region is large enough to map
  the whole grant table (it is larger or equal to gnttab_max_grant_frames()).

- interrupts: the interrupt used by Xen to inject event notifications.
  A GIC node is also required.


Example (assuming #address-cells = <2> and #size-cells = <2>):

hypervisor {
	compatible = "xen,xen-4.3", "xen,xen";
	reg = <0 0xb0000000 0 0x20000>;
	interrupts = <1 15 0xf08>;
};