net/go-tcping: for aarch64, amd64 only

The module modernc.org/sqlite (and dependencies such as modernc.org/libc)
are only available on aarch64 and amd64 FreeBSD. Other platforms are
not supported on FreeBSD right now.

Approved by: portmgr (build fix blanket)
MFH: 2026Q2

(cherry picked from commit f326a7aa4f92f51a029d825de9ef1bbc5607dbd3)