sctp: fix compile warnings in sctp_tsnmap_num_gabs

net/sctp/tsnmap.c: In function ‘sctp_tsnmap_num_gabs’:
net/sctp/tsnmap.c:347: warning: ‘start’ may be used uninitialized in this function
net/sctp/tsnmap.c:347: warning: ‘end’ may be used uninitialized in this function

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/tsnmap.c

@@ -344,7 +344,7 @@ __u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
 
 	/* Refresh the gap ack information. */
 	if (sctp_tsnmap_has_gap(map)) {
-		__u16 start, end;
+		__u16 start = 0, end = 0;
 		sctp_tsnmap_iter_init(map, &iter);
 		while (sctp_tsnmap_next_gap_ack(map, &iter,
 						&start,