Finally, convert counters in struct ifnet to counter(9).

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272244 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Remove duplicate prog.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272245 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f