[media] tvp5150: Add device tree binding document

Add a Device Tree binding document for the TVP5150 video decoder.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>