Bindings for the Cadence Xtensa Remote Processing driver.

Required properties:
- compatible: shall be "cdns,xrp".
- reg: register locations of the DSP MMIO block, DSP communication area and
  DSP shared memory area.

Optional properties:
- queue-priority: cells indicating priorities of DSP hardware queues. If
  missing then single default queue is configured.
- firmware-name: string identifying firmware name. If missing the driver
  doesn't load the firmware.

- #address-cells: number of cells DSP physical address takes in the ranges.
- #size-cells: number of cells each size takes in the ranges.
- ranges: standard ranges property. Provides mapping of DSP physical addresses
  to host physical addresses. Arbitrary number of groups with the following
  structure:
  - cells with DSP physical address of the region;
  - cells with the corresponding host physical address of the
    region;
  - cells with the size of the region.

XRP node may have an optional subnode when there's non-identity mapping set
up in the ranges property. Both subnode and ranges property are required in
order for the address translation to work.

Example:

	xrp@0 {
		#address-cells = <1>;
		#size-cells = <1>;
		compatible = "cdns,xrp";
		reg = <0xfd001000 0x00000200   /* DSP MMIO */
		       0xf0000000 0x00001000   /* DSP communication area */
		       0xf0001000 0x00fff000>; /* DSP shared memory */
		firmware-name = "xrp0.elf";
		ranges = <0x00000000 0x00000000 0x10000000
			  0x3ffc0000 0xc0000000 0x00020000
			  0x3ffe0000 0xc0020000 0x00020000
			  0x50000000 0x50000000 0x01000000
			  0x60000000 0x60000000 0x20000000
			  0xf0000000 0xf0000000 0x0d000000>;
		dsp@0 {
		};
	};
