NXP LPC32xx Clock Controller

Required properties:
- compatible: should be "nxp,lpc3220-clk"
- reg:  should contain clock controller registers location and length
- #clock-cells: must be 1, the cell holds id of a clock provided by the
  clock controller
- clocks: phandles of external oscillators, the list must contain one
  32768 Hz oscillator and may have one optional high frequency oscillator
- clock-names: list of external oscillator clock names, must contain
  "xtal_32k" and may have optional "xtal"

Examples:

	/* System Control Block */
	scb {
		compatible = "simple-bus";
		ranges = <0x0 0x040004000 0x00001000>;
		#address-cells = <1>;
		#size-cells = <1>;

		clk: clock-controller@0 {
			compatible = "nxp,lpc3220-clk";
			reg = <0x00 0x114>;
			#clock-cells = <1>;

			clocks = <&xtal_32k>, <&xtal>;
			clock-names = "xtal_32k", "xtal";
		};
	};
