* NXP PCA953x I2C GPIO multiplexer

Required properties:
 - compatible: Has to contain one of the following:
	nxp,pca9570
- #gpio-cells : Should be two. The first cell is the pin number and the 
  second cell is used to specify optional parameters (currently unused).
- gpio-controller : Marks the device node as a GPIO controller.

Example:
	i2c@7000d000 {
		gpio@48 {
			compatible = "nxp,9570";
			reg = <0x48>;
			#gpio-cells = <2>;
			gpio-controller;
		};
	};