drm/panel/panel-tpo-tpg110: fix a possible null pointer dereference

[ Upstream commit f22def5 ]

In tpg110_get_modes(), the return value of drm_mode_duplicate() is
assigned to mode, which will lead to a NULL pointer dereference on
failure of drm_mode_duplicate(). Add a check to avoid npd.

Signed-off-by: Ma Ke <make_ruc2021@163.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231009090446.4043798-1-make_ruc2021@163.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231009090446.4043798-1-make_ruc2021@163.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/gpu/drm/panel/panel-tpo-tpg110.c

@@ -379,6 +379,8 @@ static int tpg110_get_modes(struct drm_panel *panel,
 	connector->display_info.bus_flags = tpg->panel_mode->bus_flags;
 
 	mode = drm_mode_duplicate(connector->dev, &tpg->panel_mode->mode);
+	if (!mode)
+		return -ENOMEM;
 	drm_mode_set_name(mode);
 	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;