backlight: qcom-wled: Restructure the qcom-wled bindings

Binding for Qualcomm Technologies, Inc. WLED driver

Required properties:

- compatible: should be "qcom,pm8941-wled"

- reg: slave address

Optional properties:

- default-brightness: brightness value on boot, value from: 0-4095

	default: 2048

- label: The name of the backlight device

- qcom,cs-out: bool; enable current sink output

- qcom,cabc: bool; enable content adaptive backlight control

- qcom,ext-gen: bool; use externally generated modulator signal to dim

- qcom,current-limit: mA; per-string current limit; value from 0 to 25

	default: 20mA

- qcom,current-boost-limit: mA; boost current limit; one of:

	105, 385, 525, 805, 980, 1260, 1400, 1680

	default: 805mA

- qcom,switching-freq: kHz; switching frequency; one of:

	600, 640, 685, 738, 800, 872, 960, 1066, 1200, 1371,

	1600, 1920, 2400, 3200, 4800, 9600,

	default: 1600kHz

- qcom,ovp: V; Over-voltage protection limit; one of:

	27, 29, 32, 35

	default: 29V

- qcom,num-strings: #; number of led strings attached; value from 1 to 3

	default: 2

WLED (White Light Emitting Diode) driver is used for controlling display

backlight that is part of PMIC on Qualcomm Technologies, Inc. reference

platforms. The PMIC is connected to the host processor via SPMI bus.

- compatible

	Usage:        required

	Value type:   <string>

	Definition:   should be one of:

			"qcom,pm8941-wled"

			"qcom,pmi8998-wled"

			"qcom,pm660l-wled"

- reg

	Usage:        required

	Value type:   <prop encoded array>

	Definition:   Base address of the WLED modules.

- default-brightness

	Usage:        optional

	Value type:   <u32>

	Definition:   brightness value on boot, value from: 0-4095

		      Default: 2048

- label

	Usage:        required

	Value type:   <string>

	Definition:   The name of the backlight device

- qcom,cs-out

	Usage:        optional

	Value type:   <bool>

	Definition:   enable current sink output.

		      This property is supported only for PM8941.

- qcom,cabc

	Usage:        optional

	Value type:   <bool>

	Definition:   enable content adaptive backlight control.

- qcom,ext-gen

	Usage:        optional

	Value type:   <bool>

	Definition:   use externally generated modulator signal to dim.

		      This property is supported only for PM8941.

- qcom,current-limit

	Usage:        optional

	Value type:   <u32>

	Definition:   mA; per-string current limit

		      value: For pm8941: from 0 to 25 with 5 mA step

			     Default 20 mA.

			     For pmi8998: from 0 to 30 with 5 mA step

			     Default 25 mA.

- qcom,current-boost-limit

	Usage:        optional

	Value type:   <u32>

	Definition:   mA; boost current limit.

		      For pm8941: one of: 105, 385, 525, 805, 980, 1260, 1400,

		      1680. Default: 805 mA

		      For pmi8998: one of: 105, 280, 450, 620, 970, 1150, 1300,

		      1500. Default: 970 mA

- qcom,switching-freq

	Usage:        optional

	Value type:   <u32>

	 Definition:   kHz; switching frequency; one of: 600, 640, 685, 738,

		       800, 872, 960, 1066, 1200, 1371, 1600, 1920, 2400, 3200,

		       4800, 9600.

		       Default: for pm8941: 1600 kHz

				for pmi8998: 800 kHz

- qcom,ovp

	Usage:        optional

	Value type:   <u32>

	Definition:   V; Over-voltage protection limit; one of:

		      27, 29, 32, 35. default: 29V

		      This property is supported only for PM8941.

- qcom,num-strings

	Usage:        optional

	Value type:   <u32>

	Definition:   #; number of led strings attached;

		      value from 1 to 3. default: 2

		      This property is supported only for PM8941.

Example: