Qualcomm Technologies, Inc's USB Gadget

Required properties:
- compatible: Should be "qcom,usb-gadget".
- qcom,vid: VendorId to be used by composite device.

Required subnode properties:
- qcom,pid: ProductId to be used by composite device.
- qcom,composition: List of configurations where each is separated by '|'.
	And each configuration has comma separated list of functions
	specified as: <f1_name>.<f1_instance_name>,<f2_name>....
- qcom,bmAttributes: Config characteritics of composite device.
	e.g. remote wakeup capability, self or bus powered.

Optional properties:
- qcom,default-pid: ProductId to be used by composite device.
- qcom,class: Class of composite device.
- qcom,subclass: SubClass of composite device.
- qcom,protocol: Protocol of composite device.

Example:
	usb_gadget {
		compatible = "qcom,usb-gadget";
		qcom,vid = <0x05c6>;

		composition1 {
			qcom,pid = <0x9103>;
			qcom,composition = "diag.diag,ipc.ipc,gsi.rmnet,gsi.rmnet.v2x,ecm.ecm,gsi.dpl";
		};

		composition2 {
			qcom,pid = <0x9105>;
			qcom,composition = "diag.diag,gsi.dpl";
		};

		composition3 {
			qcom,pid = <0x9063>;
			qcom,composition = "gsi.rndis|gsi.ecm|gsi.mbim";
			qcom,bmAttributes = <0xa0>;
		};
	};