Berlin PWM controller

Required properties:
- compatible: should be "marvell,berlin-pwm"
- reg: physical base address and length of the controller's registers
- clocks: phandle to the input clock
- #pwm-cells: should be 3. See pwm.yaml in this directory for a description of
  the cells format.

Example:

pwm: pwm@f7f20000 {
	compatible = "marvell,berlin-pwm";
	reg = <0xf7f20000 0x40>;
	clocks = <&chip_clk CLKID_CFG>;
	#pwm-cells = <3>;
}