Device-Tree bindings for Atmel's HLCDC (High-end LCD Controller) PWM driver

The Atmel HLCDC PWM is subdevice of the HLCDC MFD device.
See ../mfd/atmel-hlcdc.txt for more details.

Required properties:
 - compatible: value should be one of the following:
   "atmel,hlcdc-pwm"
 - pinctr-names: the pin control state names. Should contain "default".
 - pinctrl-0: should contain the pinctrl states described by pinctrl
   default.
 - #pwm-cells: should be set to 3. This PWM chip use the default 3 cells
   bindings defined in pwm.txt in this directory.

Example:

	hlcdc: hlcdc@f0030000 {
		compatible = "atmel,sama5d3-hlcdc";
		reg = <0xf0030000 0x2000>;
		clocks = <&lcdc_clk>, <&lcdck>, <&clk32k>;
		clock-names = "periph_clk","sys_clk", "slow_clk";

		hlcdc_pwm: hlcdc-pwm {
			compatible = "atmel,hlcdc-pwm";
			pinctrl-names = "default";
			pinctrl-0 = <&pinctrl_lcd_pwm>;
			#pwm-cells = <3>;
		};
	};