Broadcom Kona PWM controller device tree bindings

This controller has 6 channels.

Required Properties :
- compatible: should contain "brcm,kona-pwm"
- reg: physical base address and length of the controller's registers
- clocks: phandle + clock specifier pair for the external clock
- #pwm-cells: Should be 3. See pwm.yaml in this directory for a
  description of the cells format.

Refer to clocks/clock-bindings.txt for generic clock consumer properties.

Example:

pwm: pwm@3e01a000 {
	compatible = "brcm,bcm11351-pwm", "brcm,kona-pwm";
	reg = <0x3e01a000 0xc4>;
	clocks = <&pwm_clk>;
	#pwm-cells = <3>;
};