drm/panel-edp: Add override_edid_mode quirk for generic edp

Generic edp gets mode from edid. However, some panels report incorrect
mode in this way, resulting in glitches on panel. Introduce a new quirk
additional_mode to the generic edid to pick a correct hardcoded mode.

Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231117215056.1883314-2-hsinyi@chromium.org