NVIDIA tegra isc pwm driver

This file documents the properties used by the isc-mgr driver in tegra platform

Required properties:
- compatible : Should be "nvidia, isc-pwm"
- pwms : PWM property to point to the PWM chip, chip-relative PWM number and to
         specify the period time to be used
- pwm-cells : Specify the number of cells used for the PWM chip
- npwm : number of PWMs controlled by this chip

Example:
isc_pwm: isc_pwm_gen {
    compatible = "nvidia, isc-pwm";
    pwms = <&tegra_pwm2 0 0>; /* by default the number of cells is 2 */
    #pwm-cells = <2>;
    npwm = <3>; /* number of PWMs controlled by this chip */
    status = "okay";
};