Improve consistency of the field names with tcpsinfo_t:
* Use mss instead of max_seg_size.
* Use lport and rport instead of tcp_localport and tcp_foreignport.
Use t_flags instead of flags to improve consistency with t_flags2.
Add laddr and raddr, since the addresses were missing when compared
to the output of siftr.
Reviewed by: cc
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D40834
2176c9ab71