drm/bridge: lt9611: attach to the next bridge

The bindings require that there is a next bridge after the lt9611. If
nothing else it can be the hdmi-connector (as used on the RB3 platform,
see sdm845-db845c.dts).

Bring in the next bridge into the drm bridges chain and attach to it.

Since lt9611 is not anymore the last bridge in the chain, this also
allows us to drop all the !DRM_BRIDGE_ATTACH_NO_CONNECTOR functionality.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230118081658.2198520-9-dmitry.baryshkov@linaro.org