Intel x86 PINCTRL/GPIO controller

Pin-muxing on x86 can be described with a node for the PINCTRL master
node and a set of child nodes for each pin on the SoC.

The PINCTRL master node requires the following properties:
- compatible : "intel,x86-pinctrl"

Pin nodes must be children of the pinctrl master node and can
contain the following properties:
- pad-offset        - (required) offset in the IOBASE for the pin to configured.
- gpio-offset       - (required) offset in the GPIOBASE for the pin to configured and
					also the bit shift in this register.
- mode-gpio			- (optional) standalone property to force the pin into GPIO mode.
- mode-func			- (optional) function number to assign to the pin. if 'mode-gpio'
					is set, this property will be ignored.
in case of 'mode-gpio' property set:
- output-value		- (optional) this set the default output value of the GPIO.
- direction         - (optional) this set the direction of the gpio.
- pull-str          - (optional) this set the pull strength of the pin.
- pull-assign       - (optional) this set the pull assignement (up/down) of the pin.
- invert            - (optional) this input pin is inverted

Example:

pin_usb_host_en0@0 {
    gpio-offset = <0x80 8>;
    pad-offset = <0x260>;
    mode-gpio;
    output-value = <1>;
    direction = <PIN_OUTPUT>;
};