leds: rt4505: Add DT binding document for Richtek RT4505

Add DT binding document for Richtek RT4505 flash LED controller.

Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
1 file changed