dt-bindings: leds: Add LP5860 LED controller

dt-bindings: leds: Add LP5860 LED controller

The LP5860 is a LED matrix driver with 18 constant current sinks and 11
scan switches for 198 LED dots:

  * Supply range from 2.7 V to 5.5 V
  * 0.1mA - 50mA per current sink
  * 1MHz I2C and 12MHz SPI control interface
  * 8-bit analog dimming
  * 8/16-bit PWM dimming
  * individual ON and OFF control for each LED dot
  * globat 3-bit Maximum Current setting for all LED dots
  * individual LED dot open/short detection

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20251201-v6-14-topic-ti-lp5860-v6-1-be9a21218157@pengutronix.de
Signed-off-by: Lee Jones <lee@kernel.org>