drm/dp/mst: fix a possible memory leak in fetch_monitor_name()

drm_dp_mst_get_edid call kmemdup to create mst_edid. So mst_edid need to be
freed after use.

Signed-off-by: Hangyu Hua <[e-mail]>
Reviewed-by: Lyude Paul <[e-mail]>
Signed-off-by: Lyude Paul <[e-mail]>
Cc: [e-mail]
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/dp/drm_dp_mst_topology.c

···
 
 	mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
 	drm_edid_get_monitor_name(mst_edid, name, namelen);
+	kfree(mst_edid);
 }
 
 /**