media: dt-bindings: et8ek8: Document support for flash and lens devices

Document dts support of LED/focus.

Signed-off-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/devicetree/bindings/media/i2c/toshiba,et8ek8.txt

@@ -20,6 +20,13 @@ Mandatory properties
   is in hardware standby mode when the signal is in the low state.
 
 
+Optional properties
+-------------------
+
+- flash-leds: See ../video-interfaces.txt
+- lens-focus: See ../video-interfaces.txt
+
+
 Endpoint node mandatory properties
 ----------------------------------