Richtek RT5081 flashligh led subdev
RT5081 flashlight led control.

Required properties:
- compatible : Must be "richtek,rt5081_pmu_fled";
- interrupt-names : RT5081 fled enabled interrupts.
	(R: required, O: optional)
	1.  (O)fled_strbpin: report whether the event of FLED strobe pin occurs.
	2.  (O)fled_torpin: report whether the event of FLED torch pin occures.
	3.  (O)fled_tx: report whether the event of FLED TX occurs.
	4.  (O)fled_lvp: report whether the event of FLED low VF occurs.
	5.  (R)fled2_short: report whether the event of FLED2 short occurs.
	6.  (R)fled1_short: report whether the event of FLED1 short occurs.
	7.  (O)fled2_strb: report whether the event of FLED2 strobe occurs.
	8.  (O)fled1_strb: report whether the event of FLED1 strobe occurs.
	9.  (O)fled2_strb_to: report whether the event of FLED2 strobe timeout occurs.
	10. (O)fled1_strb_to: report whether the event of FLED1 strobe timeout occurs.
	11. (O)fled2_tor: report whether the event of FLED2 torch occurs.
	12. (O)fled1_tor: repower whether the event of FLED1 torch occurs.


Optional node:
- torch_cur : 25000 ~ 400000 uA
- strobe_cur : 100000 ~  1500000 uA
- strobe_timeout : 64 ~ 2432 ms

Example:
rt5081_pmu@34 {
	status = "ok";
	compatible = "richtek,rt5081_pmu";
	reg = <0x34>;
	interrupt-controller;
	#interrupt-cells = <1>;
	rt,intr_gpio_num = <3>; /* direct defined GPIO num */
	rt,intr_gpio = <&pio 3 0>; /* genernal GPIO */
	rt5081_pmu_fled1 {
		compatible = "richtek,rt5081_pmu_fled1";
		interrupt-names = "fled_lvf", "fled2_short",
				  "fled1_short";
		torch_cur = <300000>;
		strobe_cur = <1200000>;
		strobe_timeout = <2400>;
	};
	rt5081_pmu_fled2 {
		compatible = "richtek,rt5081_pmu_fled2";
		interrupt-names = "fled_lvf", "fled2_short",
				  "fled1_short";
		torch_cur = <200000>;
		strobe_cur = <1000000>;
		strobe_timeout = <1200>;
	};
};
