dt-bindings: leds: sgm3140: Document ocp8110 compatible

Add devicetree binding for Orient Chip OCP8110 charge pump used for
camera flash LEDs.

Signed-off-by: André Apitzsch <git@apitzsch.eu>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220505185344.10067-1-git@apitzsch.eu


Signed-off-by: Rob Herring <robh@kernel.org>