* Designware APB timer

Required properties:
- compatible: "snps,dw-apb-timer-sp" or "snps,dw-apb-timer-osc"
- reg: physical base address of the controller and length of memory mapped
  region.
- interrupts: IRQ line for the timer.
- either clocks+clock-names or clock-frequency properties

Optional properties:
- clocks	: list of clock specifiers, corresponding to entries in
		  the clock-names property;
- clock-names	: should contain "timer" and "pclk" entries, matching entries
		  in the clocks property.
- clock-frequency: The frequency in HZ of the timer.
- clock-freq: For backwards compatibility with picoxcell

If using the clock specifiers, the pclk clock is optional, as not all
systems may use one.


Example:

		timer1: timer@ffc09000 {
				compatible = "snps,dw-apb-timer-sp";
				interrupts = <0 168 4>;
				clock-frequency = <200000000>;
				reg = <0xffc09000 0x1000>;
			};

		timer2: timer@ffd00000 {
				compatible = "snps,dw-apb-timer-osc";
				interrupts = <0 169 4>;
				clock-frequency = <200000000>;
				reg = <0xffd00000 0x1000>;
			};

		timer3: timer@ffe00000 {
				compatible = "snps,dw-apb-timer-osc";
				interrupts = <0 170 4>;
				reg = <0xffe00000 0x1000>;
				clocks = <&timer_clk>, <&timer_pclk>;
				clock-names = "timer", "pclk";
			};