Defined the needed library to convert usr.sbin to LIBADD


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275052 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
o Add Virtio MMIO bus driver to config
o Move Virtio-related to common config file


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275053 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Convert usr.sbin to LIBADD
Reduce overlinking


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275054 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f