The output port endpoints can be connected to USB-C connectors.
Running drm_of_find_panel_or_bridge() with such endpoints leads to
a continuous return value of -EPROBE_DEFER, even though there is
no panel present.
To avoid this, check for the existence of a "mode-switch" property in
the port endpoint, and skip panel registration completely if so.
Signed-off-by: Pin-yen Lin <treapking@xxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>