VIA/Wondermedia VT8500/WM8xxx series SoC PWM controller

Required properties:
- compatible: should be "via,vt8500-pwm"
- reg: physical base address and length of the controller's registers
- #pwm-cells: Should be 3. Number of cells being used to specify PWM property.
  First cell specifies the per-chip index of the PWM to use, the second
  cell is the period in nanoseconds and bit 0 in the third cell is used to
  encode the polarity of PWM output. Set bit 0 of the third in PWM specifier
  to 1 for inverse polarity & set to 0 for normal polarity.
- clocks: phandle to the PWM source clock

Example:

pwm1: pwm@d8220000 {
	#pwm-cells = <3>;
	compatible = "via,vt8500-pwm";
	reg = <0xd8220000 0x1000>;
	clocks = <&clkpwm>;
};
