[media] adv7604: Add endpoint properties to DT bindings

Add support for the hsync-active, vsync-active and pclk-sample
properties to the DT bindings and control BT.656 mode implicitly.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>