After the changes in r274118 make NOIP kernels compile by hiding an
otherwise unused variable declaration behind INET6 || INET.

MFC after:	27 days
X-MFS with:	r274118


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274173 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f