remoteproc: dt: Provide bindings for ST's Remote Processor Controller driver

STMicroelectronics Co-Processor Bindings

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This binding provides support for adjunct processors found on ST SoCs.

Co-processors can be controlled from the bootloader or the primary OS. If

the bootloader starts a co-processor, the primary OS must detect its state

and act accordingly.

Required properties:

- compatible		Should be one of:

				"st,st231-rproc"

				"st,st40-rproc"

- memory-region		Reserved memory (See: ../reserved-memory/reserved-memory.txt)

- resets		Reset lines (See: ../reset/reset.txt)

- reset-names		Must be "sw_reset" and "pwr_reset"

- clocks		Clock for co-processor (See: ../clock/clock-bindings.txt)

- clock-frequency	Clock frequency to set co-processor at if the bootloader

			hasn't already done so

- st,syscfg		System configuration register which holds the boot vector

			for the co-processor

				1st cell: Phandle to syscon block

				2nd cell: Boot vector register offset

Example:

	audio_reserved: rproc@42000000 {

		compatible = "shared-dma-pool";

		reg = <0x42000000 0x01000000>;

		no-map;

	};

	st231-audio {

		compatible	= "st,st231-rproc";

		memory-region	= <&audio_reserved>;

		resets		= <&softreset STIH407_ST231_AUD_SOFTRESET>;

		reset-names	= "sw_reset";

		clocks		= <&clk_s_c0_flexgen CLK_ST231_AUD_0>;

		clock-frequency	= <600000000>;

		st,syscfg	= <&syscfg_core 0x228>;

	};