drm/bridge: tc358767: move video stream setup to tc_main_link_stream

The driver currently sets the video stream registers in
tc_main_link_setup. One should be able to establish the DP link without
any video stream, so a more logical place is to configure the stream in
the tc_main_link_stream. So move them there.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528082747.3631-8-tomi.valkeinen@ti.com