net/mad_fcl: fix build on 15-CURRENT

Link with -lutil to get ftime(), which was moved there in 15-CURRENT.
This is harmless on older FreeBSD versions.

While we are at it, define LICENSE.

MFH: 2024Q4
(cherry picked from commit bec3162cc0d7607405ac59a6e6e93a03cfabfa3f)