netstat: add support for UDP-Lite endpoints

With this patch UDP-Lite endpoints are also shown per default.

Approved by: re (cperciva)
Reviewed by: Nick Banks
Differential Revision: https://reviews.freebsd.org/D53252

(cherry picked from commit c2b08c13c20d44c3368bcbf738624e5fac461314)
(cherry picked from commit 372b60422689b2bfb2ccf3ab22847eb54dae0b11)