drm/rockchip: add DRM_BRIDGE_ATTACH_NO_CONNECTOR flag to drm_bridge_attach

Commit a25b988f ("drm/bridge: Extend bridge API to disable connector creation")
added DRM_BRIDGE_ATTACH_NO_CONNECTOR bridge flag and all bridges handle
this flag in some way since then.
Newly added bridge drivers must no longer contain the connector creation and
will fail probing if this flag isn't set.

In order to be able to connect to those newly added bridges as well,
make use of drm_bridge_connector API and have the connector initialized
by the display controller.

Signed-off-by: Alex Bee <knaerzche@gmail.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210913125108.195704-1-knaerzche@gmail.com