packetizer: mlp: initialize all callback fields

Signed-off-by: Thomas Guillem <thomas@gllm.fr>

modules/packetizer/mlp.c

@@ -494,6 +494,7 @@ static int Open( vlc_object_t *p_this )
     /* Set callback */
     p_dec->pf_packetize = Packetize;
     p_dec->pf_flush     = Flush;
+    p_dec->pf_get_cc    = NULL;
     return VLC_SUCCESS;
 }