Use new drm_bridge_connector_mode_valid() helper if there is a HDMI
bridge in the bridge chain. This removes the need to perform TMDS char
rate check manually in the bridge driver.
Reviewed-by: Chen-Yu Tsai <wens@xxxxxxxx>
Reviewed-by: Maxime Ripard <mripard@xxxxxxxxxx>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>