tcp, udp: improve input validation in handling bind()

Reported by: syzbot+24fcfd8057e9bc339295@syzkaller.appspotmail.com
Reported by: syzbot+6e90ceb5c89285b2655b@syzkaller.appspotmail.com
Reviewed by: markj, rscheff
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D31422

(cherry picked from commit 3f1f6b6ef7f6fea63583a4b6e917b3cc0f0d525e)