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

commit 6e03b13cc7d9427c2c77feed1549191015615202 upstream.

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 <hbh25y@gmail.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: stable@vger.kernel.org
Link: https://patchwork.freedesktop.org/patch/msgid/20220516032042.13166-1-hbh25y@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index bb70c52..efd3ac2 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2830,6 +2830,7 @@
 
 	mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
 	drm_edid_get_monitor_name(mst_edid, name, namelen);
+	kfree(mst_edid);
 }
 
 /**