dt-bindings: pwm: Update bindings for MT7629 SoC

   - "pwm1-8": the eight per PWM clocks for mt2712

   - "pwm1-6": the six per PWM clocks for mt7622

   - "pwm1-5": the five per PWM clocks for mt7623

   - "pwm1"  : the PWM1 clock for mt7629

 - pinctrl-names: Must contain a "default" entry.

 - pinctrl-0: One property must exist for each entry in pinctrl-names.

   See pinctrl/pinctrl-bindings.txt for details of the property values.

Optional properties:

- assigned-clocks: Reference to the PWM clock entries.

- assigned-clock-parents: The phandle of the parent clock of PWM clock.

Example:

	pwm0: pwm@11006000 {

		compatible = "mediatek,mt7623-pwm";