dt-bindings: Document the hi3660 reset bindings

Hisilicon System Reset Controller

======================================

Please also refer to reset.txt in this directory for common reset

controller binding usage.

The reset controller registers are part of the system-ctl block on

hi3660 SoC.

Required properties:

- compatible: should be

		 "hisilicon,hi3660-reset"

- hisi,rst-syscon: phandle of the reset's syscon.

- #reset-cells : Specifies the number of cells needed to encode a

  reset source.  The type shall be a <u32> and the value shall be 2.

	 Cell #1 : offset of the reset assert control

	           register from the syscon register base

		   offset + 4: deassert control register

		   offset + 8: status control register

	 Cell #2 : bit position of the reset in the reset control register

Example:

	iomcu: iomcu@ffd7e000 {

		compatible = "hisilicon,hi3660-iomcu", "syscon";

		reg = <0x0 0xffd7e000 0x0 0x1000>;

	};

	iomcu_rst: iomcu_rst_controller {

		compatible = "hisilicon,hi3660-reset";

		hisi,rst-syscon = <&iomcu>;

		#reset-cells = <2>;

	};

Specifying reset lines connected to IP modules

==============================================

example:

        i2c0: i2c@..... {

                ...

		resets = <&iomcu_rst 0x20 3>; /* offset: 0x20; bit: 3 */

                ...

        };