Qualcomm's PM8941 USB ID Extcon device

Some Qualcomm PMICs have a "misc" module that can be used to detect when
the USB ID pin has been pulled low or high.

PROPERTIES

- compatible:
    Usage: required
    Value type: <string>
    Definition: Should contain "qcom,pm8941-misc";

- reg:
    Usage: required
    Value type: <u32>
    Definition: Should contain the offset to the misc address space

- interrupts:
    Usage: required
    Value type: <prop-encoded-array>
    Definition: Should contain the usb id interrupt

- interrupt-names:
    Usage: required
    Value type: <stringlist>
    Definition: Should contain the string "usb_id" for the usb id interrupt

Example:

	pmic {
		usb_id: misc@900 {
			compatible = "qcom,pm8941-misc";
			reg = <0x900>;
			interrupts = <0x0 0x9 0 IRQ_TYPE_EDGE_BOTH>;
			interrupt-names = "usb_id";
		};
	}

	usb-controller {
		extcon = <&usb_id>;
	};