docs: ABI: unify /sys/class/leds/<led>/brightness documentation

This ABI is defined twice, one for normal leds and another
one for multicolor ones.

Ensure that just one definition is there at ABI.

Acked-by: Pavel Machek <[e-mail]>
Acked-by: Jonathan Corbet <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>
Link: https://lore.kernel.org/r/111502[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/ABI/testing/sysfs-class-led

···
 KernelVersion:	2.6.17
 Contact:	Richard Purdie <[e-mail]>
 Description:
-		Set the brightness of the LED. Most LEDs don't
-		have hardware brightness support, so will just be turned on for
-		non-zero brightness settings. The value is between 0 and
+		Set the brightness of the LED.
+
+		Most LEDs don't have hardware brightness support, so will
+		just be turned on for non-zero brightness settings.
+
+		.. Note::
+
+		  For multicolor LEDs, writing to this file will update all
+		  LEDs within the group to a calculated percentage of what
+		  each color LED intensity is set to.
+
+		  The percentage is calculated for each grouped LED via
+		  the equation below::
+
+		    led_brightness = brightness * multi_intensity/max_brightness
+
+		  For additional details please refer to
+		  Documentation/leds/leds-class-multicolor.rst.
+
+		The value is between 0 and
 		/sys/class/leds/<led>/max_brightness.
 
 		Writing 0 to this file clears active trigger.
 
 		Writing non-zero to this file while trigger is active changes the
 		top brightness trigger is going to use.
+
+
 
 What:		/sys/class/leds/<led>/max_brightness
 Date:		March 2006

Documentation/ABI/testing/sysfs-class-led-multicolor

···
-What:		/sys/class/leds/<led>/brightness
-Date:		March 2020
-KernelVersion:	5.9
-Contact:	Dan Murphy <[e-mail]>
-Description:	read/write
-		Writing to this file will update all LEDs within the group to a
-		calculated percentage of what each color LED intensity is set
-		to. The percentage is calculated for each grouped LED via the
-		equation below:
-
-		led_brightness = brightness * multi_intensity/max_brightness
-
-		For additional details please refer to
-		Documentation/leds/leds-class-multicolor.rst.
-
-		The value of the LED is from 0 to
-		/sys/class/leds/<led>/max_brightness.
 
 What:		/sys/class/leds/<led>/multi_index
 Date:		March 2020
···
 		as an array of strings as they are indexed in the
 		multi_intensity file.
 
+		For additional details please refer to
+		Documentation/leds/leds-class-multicolor.rst.
+
 What:		/sys/class/leds/<led>/multi_intensity
 Date:		March 2020
 KernelVersion:	5.9
···
 		This file contains array of integers. Order of components is
 		described by the multi_index array. The maximum intensity should
 		not exceed /sys/class/leds/<led>/max_brightness.
+
+		For additional details please refer to
+		Documentation/leds/leds-class-multicolor.rst.