Freescale i.MX PWM controller

Required properties:
- compatible : should be "fsl,<soc>-pwm" and one of the following
   compatible strings:
  - "fsl,imx1-pwm" for PWM compatible with the one integrated on i.MX1
  - "fsl,imx27-pwm" for PWM compatible with the one integrated on i.MX27
- reg: physical base address and length of the controller's registers
- #pwm-cells: 2 for i.MX1 and 3 for i.MX27 and newer SoCs. See pwm.yaml
  in this directory for a description of the cells format.
- clocks : Clock specifiers for both ipg and per clocks.
- clock-names : Clock names should include both "ipg" and "per"
See the clock consumer binding,
	Documentation/devicetree/bindings/clock/clock-bindings.txt
- interrupts: The interrupt for the pwm controller

Example:

pwm1: pwm@53fb4000 {
	#pwm-cells = <3>;
	compatible = "fsl,imx53-pwm", "fsl,imx27-pwm";
	reg = <0x53fb4000 0x4000>;
	clocks = <&clks IMX5_CLK_PWM1_IPG_GATE>,
		 <&clks IMX5_CLK_PWM1_HF_GATE>;
	clock-names = "ipg", "per";
	interrupts = <61>;
};