leds: st1202: Correct and extend hw_pattern documentation

Fix the repeat section: -1 is a valid value meaning infinite repeat,
as accepted by the ledtrig-pattern sysfs interface; only 0 and values
below -1 are rejected. The previous text incorrectly stated all negative
numbers were invalid. Also remove the redundant trailing sentence since
the behaviour is now covered inline.

Add the brightness range (0-255) to the hw_pattern section, which was
previously undocumented.

Fixes: b1816b2238 ("Documentation:leds: Add leds-st1202.rst")
Signed-off-by: Manuel Fombuena <fombuena@outlook.com>
Assisted-by: Claude:claude-sonnet-4-6
Link: https://patch.msgid.link/GV1PR08MB8497B2FB4F5AC4B142790CE5C5F52@GV1PR08MB8497.eurprd08.prod.outlook.com
Signed-off-by: Lee Jones <lee@kernel.org>

Documentation/leds/leds-st1202.rst

@@ -16,6 +16,7 @@ in terms of PWM duty-cycle and duration (ms).
 To be compatible with the hardware pattern format, maximum 8 tuples of
 brightness (PWM) and duration must be written to hw_pattern.
 
+- Brightness range: 0-255
 - Min pattern duration: 22 ms
 - Max pattern duration: 5610 ms
 
@@ -26,9 +27,7 @@ The format of the hardware pattern values should be:
 ----------------------------
 
 Specify a pattern repeat number, which is common for all channels.
-Default is 1; negative numbers and 0 are invalid.
+Default is 1. Writing 0 is invalid. Writing -1 or 255 repeats the
+pattern indefinitely.
 
 This file will always return the originally written repeat number.
-
-When the 255 value is written to it, all patterns will repeat
-indefinitely.