[media] Documentation: DT: add bindings for ST HVA

st-hva: multi-format video encoder for STMicroelectronics SoC.

Required properties:

- compatible: should be "st,st-hva".

- reg: HVA physical address location and length, esram address location and

  length.

- reg-names: names of the registers listed in registers property in the same

  order.

- interrupts: HVA interrupt number.

- clocks: from common clock binding: handle hardware IP needed clocks, the

  number of clocks may depend on the SoC type.

  See ../clock/clock-bindings.txt for details.

- clock-names: names of the clocks listed in clocks property in the same order.

Example:

	hva@8c85000{

		compatible = "st,st-hva";

		reg = <0x8c85000 0x400>, <0x6000000 0x40000>;

		reg-names = "hva_registers", "hva_esram";

		interrupts = <GIC_SPI 58 IRQ_TYPE_NONE>,

			     <GIC_SPI 59 IRQ_TYPE_NONE>;

		clock-names = "clk_hva";

		clocks = <&clk_s_c0_flexgen CLK_HVA>;

	};