[PKT_SCHED]: Add missing MODULE_LICENSE.

Signed-off-by: Pozsar Balazs <pozsy@uhulinux.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_atm.c

@@ -714,3 +714,4 @@ static void __exit atm_exit(void)
 
 module_init(atm_init)
 module_exit(atm_exit)
+MODULE_LICENSE("GPL");