dt-bindings: Add qcom slimbus controller bindings

Qualcomm SLIMbus controller

This controller is used if applications processor driver controls SLIMbus

master component.

Required properties:

 - #address-cells - refer to Documentation/devicetree/bindings/slimbus/bus.txt

 - #size-cells	- refer to Documentation/devicetree/bindings/slimbus/bus.txt

 - reg : Offset and length of the register region(s) for the device

 - reg-names : Register region name(s) referenced in reg above

	 Required register resource entries are:

	 "ctrl": Physical address of controller register blocks

 	 "slew": required for "qcom,apq8064-slim" SOC.

 - compatible : should be "qcom,<SOC-NAME>-slim" for SOC specific compatible

 		followed by "qcom,slim" for fallback.

 - interrupts : Interrupt number used by this controller

 - clocks : Interface and core clocks used by this SLIMbus controller

 - clock-names : Required clock-name entries are:

	"iface" : Interface clock for this controller

	"core" : Interrupt for controller core's BAM

Example:

	slim@28080000 {

		compatible = "qcom,apq8064-slim", "qcom,slim";

		reg = <0x28080000 0x2000>, <0x80207C 4>;

		reg-names = "ctrl", "slew";

		interrupts = <0 33 0>;

		clocks = <&lcc SLIMBUS_SRC>, <&lcc AUDIO_SLIMBUS_CLK>;

		clock-names = "iface", "core";

		#address-cells = <2>;

		#size-cell = <0>;

		wcd9310: audio-codec@1,0{

			compatible = "slim217,60";

			reg = <1 0>;

		};

	};