Freescale i.MX PWM controller

Required properties:
- compatible: should be "fsl,<soc>-pwm"
- reg: physical base address and length of the controller's registers
- #pwm-cells: should be 2.  The first cell specifies the per-chip index
  of the PWM to use and the second cell is the period in nanoseconds.
- interrupts: The interrupt for the pwm controller

Example:

pwm1: pwm@53fb4000 {
	#pwm-cells = <2>;
	compatible = "fsl,imx53-pwm", "fsl,imx27-pwm";
	reg = <0x53fb4000 0x4000>;
	interrupts = <61>;
};
