Device tree bindings for fan tach output connected to PWM controller with
PWM capture capability.

Required properties:
- compatible	: "generic-pwm-tachometer"
- pwms		: PWM handle. Please refer pwm.txt DT binding for more details.

Example:

	tegra_tachometer: tachometer@39c0000 {
		compatible = "nvidia,pwm-tegra194-tachometer";
		reg = <0x0 0x039c0000 0x0 0x10>;
		clocks = <&bpmp_clks TEGRA194_CLK_TACH>;
		clock-names = "tach";
		resets = <&bpmp_resets TEGRA194_RESET_TACH>;
		reset-names = "tach";
		pulse-per-rev = <2>;
		sampling-window = <2>;
	};

	generic_pwm_tachometer {
		compatible = "generic-pwm-tachometer";
		pwms = <&tegra_tachometer 0 1000000>;
	};