drm/msm/dsi: Support NO_CONNECTOR bridges

For now, since we have a mix of bridges which support this flag, which
which do *not* support this flag, or work both ways, try it once with
NO_CONNECTOR and then fall back to the old way if that doesn't work.
Eventually we can drop the fallback path.

v2: Add missing drm_connector_attach_encoder() so display actually comes
    up when the bridge properly handles the NO_CONNECTOR flag

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20210920225801.227211-2-robdclark@gmail.com


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>