misc: dt-bindings: Add Qualcomm Fastrpc bindings

Qualcomm Technologies, Inc. FastRPC Driver

The FastRPC implements an IPC (Inter-Processor Communication)

mechanism that allows for clients to transparently make remote method

invocations across DSP and APPS boundaries. This enables developers

to offload tasks to the DSP and free up the application processor for

other tasks.

- compatible:

	Usage: required

	Value type: <stringlist>

	Definition: must be "qcom,fastrpc"

- label

	Usage: required

	Value type: <string>

	Definition: should specify the dsp domain name this fastrpc

	corresponds to. must be one of this: "adsp", "mdsp", "sdsp", "cdsp"

- #address-cells

	Usage: required

	Value type: <u32>

	Definition: Must be 1

- #size-cells

	Usage: required

	Value type: <u32>

	Definition: Must be 0

= COMPUTE BANKS

Each subnode of the Fastrpc represents compute context banks available

on the dsp.

- All Compute context banks MUST contain the following properties:

- compatible:

	Usage: required

	Value type: <stringlist>

	Definition: must be "qcom,fastrpc-compute-cb"

- reg

	Usage: required

	Value type: <u32>

	Definition: Context Bank ID.

- qcom,nsessions:

	Usage: Optional

	Value type: <u32>

	Defination: A value indicating how many sessions can share this

		    context bank. Defaults to 1 when this property

		    is not specified.

Example:

adsp-pil {

	compatible = "qcom,msm8996-adsp-pil";

	...

	smd-edge {

		label = "lpass";

		fastrpc {

			compatible = "qcom,fastrpc";

			qcom,smd-channels = "fastrpcsmd-apps-dsp";

			label = "adsp";

			#address-cells = <1>;

			#size-cells = <0>;

			cb@1 {

				compatible = "qcom,fastrpc-compute-cb";

				reg = <1>;

			};

			cb@2 {

				compatible = "qcom,fastrpc-compute-cb";

				reg = <2>;

			};

			...

		};

	};

};