media: dt-bindings: ov5693: document YAML binding

Add documentation of device tree in YAML schema for the OV5693
CMOS image sensor from Omnivision

Signed-off-by: Tommaso Merciai <tommaso.merciai@amarulasolutions.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>