MSM GPIO controller bindings

Required properties:
- compatible:
  - "qcom,msm-gpio" for MSM controllers
- #gpio-cells : Should be two.
  - first cell is the pin number
  - second cell is used to specify optional parameters (unused)
- gpio-controller : Marks the device node as a GPIO controller.
- #interrupt-cells : Should be 2.
- interrupt-controller: Mark the device node as an interrupt controller

Example:

	msmgpio: gpio@fd510000 {
		compatible = "qcom,msm-gpio";
		gpio-controller;
		#gpio-cells = <2>;
		interrupt-controller;
		#interrupt-cells = <2>;
		reg = <0xfd510000 0x4000>;
	};

To specify gpios for a device:

	device1@f991f000 {
		compatible = "qcom,msm-device-v1";
		reg = <0xf991f000 0x1000>;
		gpios = <&msmgpio 45 0>;
		cs-gpios = <&msmgpio 46 0>;
	};

45, 46 - gpio numbers.
The driver for device1 can call of_get_gpio() to extract the
gpio45. In order to extract gpio46, the driver needs to call
of_get_named_gpio with "cs-gpios" as the name parameter.
Please refer to the file: include/linux/of_gpio.h for the
complete list of APIs the driver can use to extract gpio
information from the device tree.
