drm/bridge: tc358767: add drm_panel_bridge support

drm/bridge: tc358767: add drm_panel_bridge support

With the bridge operations implemented the last step to prepare
this driver for a chained setup is the use of the bridge panel driver.

The bridge panel driver is only used when a port@2 is present in
the DT. So when the display driver requests a connector
support both situations:
- connector created by bridge panel driver
- connector created by this driver

And on top, support that the display driver creates the connector,
which is the preferred setup.

Note: the bridge panel will use the connector type from the panel.

v3:
  - Fix wrong logic in connector creation (Laurent)

v2:
  - Merge connector and drm_panel_bridge patches
    and fix so we do not create two connectors (Laurent)

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Jonas Karlman <jonas@kwiboo.se>
Cc: Jernej Skrabec <jernej.skrabec@siol.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200727170320.959777-4-sam@ravnborg.org