fsm_vty: use unsigned int when left-shifting 31 bits!

fsm_vty.c:64:8: runtime error: left shift of 1 by 31 places cannot be represented in type 'int'

Change-Id: I637bce52fae947922cbb8642a0313d174c827422
diff --git a/src/vty/fsm_vty.c b/src/vty/fsm_vty.c
index 025d0d8..777d38c 100644
--- a/src/vty/fsm_vty.c
+++ b/src/vty/fsm_vty.c
@@ -61,7 +61,7 @@
 	if (fsm->event_names) {
 		for (evt_name = fsm->event_names; evt_name->str != NULL; evt_name++) {
 			vty_out(vty, "%s Event %02u (0x%08x): '%s'%s", prefix, evt_name->value,
-				(1 << evt_name->value), evt_name->str, VTY_NEWLINE);
+				(1U << evt_name->value), evt_name->str, VTY_NEWLINE);
 		}
 	} else
 		vty_out(vty, "%s No event names are defined for this FSM! Please fix!%s", prefix, VTY_NEWLINE);