net/sniffnet: update to 1.3.1

While here, remove BROKEN on i386 and enable build for SSE2-capable
CPUs.[1]

Changelog: https://github.com/GyulyVGC/sniffnet/releases/tag/v1.3.1

Reported by: GitHub (watch releases)
Obtained from: https://cgit.freebsd.org/ports/tree/games/jumpy/Makefile#n31 [1]