devicetree: Add bindings for the ATH79 reset controller

Binding for Qualcomm Atheros AR7xxx/AR9XXX reset controller

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

controller binding usage.

Required Properties:

- compatible: has to be "qca,<soctype>-reset", "qca,ar7100-reset"

              as fallback

- reg: Base address and size of the controllers memory area

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

                 line, should be 1

Example:

	reset-controller@1806001c {

		compatible = "qca,ar9132-reset", "qca,ar7100-reset";

		reg = <0x1806001c 0x4>;

		#reset-cells = <1>;

	};