Binding for the AXS10x reset controller

This binding describes the ARC AXS10x boards custom IP-block which allows
to control reset signals of selected peripherals. For example DW GMAC, etc...
This block is controlled via memory-mapped register (AKA CREG) which
represents up-to 32 reset lines.

As of today only the following lines are used:
 - DW GMAC - line 5

This binding uses the common reset binding[1].

[1] Documentation/devicetree/bindings/reset/reset.txt

Required properties:
- compatible: should be "snps,axs10x-reset".
- reg: should always contain pair address - length: for creg reset
  bits register.
- #reset-cells: from common reset binding; Should always be set to 1.

Example:
	reset: reset-controller@11220 {
		compatible = "snps,axs10x-reset";
		#reset-cells = <1>;
		reg = <0x11220 0x4>;
	};

Specifying reset lines connected to IP modules:
	ethernet@.... {
		....
		resets = <&reset 5>;
		....
	};
