dt-bindings: add bindings for i2c-pca-platform

* NXP PCA PCA9564/PCA9665 I2C controller

The PCA9564/PCA9665 serves as an interface between most standard

parallel-bus microcontrollers/microprocessors and the serial I2C-bus

and allows the parallel bus system to communicate bi-directionally

with the I2C-bus.

Required properties :

 - reg : Offset and length of the register set for the device

 - compatible : one of "nxp,pca9564" or "nxp,pca9665"

Optional properties

 - interrupts : the interrupt number

 - interrupt-parent : the phandle for the interrupt controller.

   If an interrupt is not specified polling will be used.

 - reset-gpios : gpio specifier for gpio connected to RESET_N pin. As the line

   is active low, it should be marked GPIO_ACTIVE_LOW.

 - clock-frequency : I2C bus frequency.

Example:

	i2c0: i2c@80000 {

		compatible = "nxp,pca9564";

		#address-cells = <1>;

		#size-cells = <0>;

		reg = <0x80000 0x4>;

		reset-gpios = <&gpio1 0 GPIO_ACTIVE_LOW>;

		clock-frequency = <100000>;

	};