* Pistachio general-purpose timer based clocksource

Required properties:
 - compatible: "img,pistachio-gptimer".
 - reg: Address range of the timer registers.
 - interrupts: An interrupt for each of the four timers
 - clocks: Should contain a clock specifier for each entry in clock-names
 - clock-names: Should contain the following entries:
                "sys", interface clock
                "slow", slow counter clock
                "fast", fast counter clock
 - img,cr-periph: Must contain a phandle to the peripheral control
		  syscon node.

Example:
	timer: timer@18102000 {
		compatible = "img,pistachio-gptimer";
		reg = <0x18102000 0x100>;
		interrupts = <GIC_SHARED 60 IRQ_TYPE_LEVEL_HIGH>,
			     <GIC_SHARED 61 IRQ_TYPE_LEVEL_HIGH>,
			     <GIC_SHARED 62 IRQ_TYPE_LEVEL_HIGH>,
			     <GIC_SHARED 63 IRQ_TYPE_LEVEL_HIGH>;
		clocks = <&clk_periph PERIPH_CLK_COUNTER_FAST>,
		         <&clk_periph PERIPH_CLK_COUNTER_SLOW>,
			 <&cr_periph SYS_CLK_TIMER>;
		clock-names = "fast", "slow", "sys";
		img,cr-periph = <&cr_periph>;
	};
