leds: lp8864: Add support for Texas Instruments LP8864, LP8864S, LP8866 LED-backlights

Add driver for TI LP8864, LP8864S, LP8866 4/6 channel LED-backlight drivers
with I2C interface.

Link: https://www.ti.com/lit/gpn/lp8864-q1
Link: https://www.ti.com/lit/gpn/lp8864s-q1
Link: https://www.ti.com/lit/gpn/lp8866-q1
Link: https://www.ti.com/lit/gpn/lp8866s-q1


Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Link: https://lore.kernel.org/r/20241218210829.73191-3-alexander.sverdlin@siemens.com


Signed-off-by: Lee Jones <lee@kernel.org>