dt-binding: soc: qcom: Add binding for rmtfs memory

Qualcomm Remote File System Memory binding

This binding describes the Qualcomm remote filesystem memory, which serves the

purpose of describing the shared memory region used for remote processors to

access block device data using the Remote Filesystem protocol.

- compatible:

	Usage: required

	Value type: <stringlist>

	Definition: must be:

		    "qcom,rmtfs-mem"

- reg:

	Usage: required for static allocation

	Value type: <prop-encoded-array>

	Definition: must specify base address and size of the memory region,

		    as described in reserved-memory.txt

- size:

	Usage: required for dynamic allocation

	Value type: <prop-encoded-array>

	Definition: must specify a size of the memory region, as described in

		    reserved-memory.txt

- qcom,client-id:

	Usage: required

	Value type: <u32>

	Definition: identifier of the client to use this region for buffers.

- qcom,vmid:

	Usage: optional

	Value type: <u32>

	Definition: vmid of the remote processor, to set up memory protection.

= EXAMPLE

The following example shows the remote filesystem memory setup for APQ8016,

with the rmtfs region for the Hexagon DSP (id #1) located at 0x86700000.

	reserved-memory {

		#address-cells = <2>;

		#size-cells = <2>;

		ranges;

		rmtfs@86700000 {

			compatible = "qcom,rmtfs-mem";

			reg = <0x0 0x86700000 0x0 0xe0000>;

			no-map;

			qcom,client-id = <1>;

		};

	};