CVE-2023-52821

drm/panel: fix a possible null pointer dereference

In the Linux kernel, the following vulnerability has been resolved: drm/panel: fix a possible null pointer dereference In versatile_panel_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.