Device-Tree bindings for ST IRB IP

Required properties:
	- compatible: Should contain "st,comms-irb".
	- reg: Base physical address of the controller and length of memory
	  mapped region.
	- interrupts: interrupt-specifier for the sole interrupt generated by
	  the device. The interrupt specifier format depends on the interrupt
	  controller parent.
	- rx-mode: can be "infrared" or "uhf". This property specifies the L1
	  protocol used for receiving remote control signals. rx-mode should
	  be present iff the rx pins are wired up.
	- tx-mode: should be "infrared". This property specifies the L1
	  protocol used for transmitting remote control signals. tx-mode should
	  be present iff the tx pins are wired up.

Optional properties:
	- pinctrl-names, pinctrl-0: the pincontrol settings to configure muxing
	  properly for IRB pins.
	- clocks : phandle with clock-specifier pair for IRB.

Example node:

	rc: rc@fe518000 {
		compatible	= "st,comms-irb";
		reg		= <0xfe518000 0x234>;
		interrupts	= <0 203 0>;
		rx-mode		= "infrared";
	};
