[media] bindings for stih-cec driver

STMicroelectronics STIH4xx HDMI CEC driver

Required properties:

 - compatible : value should be "st,stih-cec"

 - reg : Physical base address of the IP registers and length of memory

	 mapped region.

 - clocks : from common clock binding: handle to HDMI CEC clock

 - interrupts : HDMI CEC interrupt number to the CPU.

 - pinctrl-names: Contains only one value - "default"

 - pinctrl-0: Specifies the pin control groups used for CEC hardware.

 - resets: Reference to a reset controller

Example for STIH407:

sti-cec@094a087c {

	compatible = "st,stih-cec";

	reg = <0x94a087c 0x64>;

	clocks = <&clk_sysin>;

	clock-names = "cec-clk";

	interrupts = <GIC_SPI 140 IRQ_TYPE_NONE>;

	interrupt-names = "cec-irq";

	pinctrl-names = "default";

	pinctrl-0 = <&pinctrl_cec0_default>;

	resets = <&softreset STIH407_LPM_SOFTRESET>;

};