media: dt-bindings: smia: Add "rotation" property

Add the rotation property to list of optional properties for the smia
sensors.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/devicetree/bindings/media/i2c/nokia,smia.txt

@@ -29,6 +29,9 @@ Optional properties
 - reset-gpios: XSHUTDOWN GPIO
 - flash-leds: See ../video-interfaces.txt
 - lens-focus: See ../video-interfaces.txt
+- rotation: Integer property; valid values are 0 (sensor mounted upright)
+	    and 180 (sensor mounted upside down). See
+	    ../video-interfaces.txt .
 
 
 Endpoint node mandatory properties