Device-Tree bindings for GPIO IR receiver

Required properties:
	- compatible: should be "gpio-ir-receiver".
	- gpios: specifies GPIO used for IR signal reception.

Optional properties:
	- linux,rc-map-name: see rc.txt file in the same
	  directory.

Example node:

	ir: ir-receiver {
		compatible = "gpio-ir-receiver";
		gpios = <&gpio0 19 1>;
		linux,rc-map-name = "rc-rc6-mce";
	};