media: dt-bindings: add bindings for Toshiba TC358746

Add the bindings for the Toshiba TC358746 Parallel <-> MIPI-CSI bridge
driver.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>