In r288122, we changed vm_page_unwire() so that it returns a Boolean
authoralc <alc@FreeBSD.org>
Wed, 20 Sep 2017 04:59:52 +0000 (04:59 +0000)
committeralc <alc@FreeBSD.org>
Wed, 20 Sep 2017 04:59:52 +0000 (04:59 +0000)
commit98c7e4b2b1ab179357019a7249c718af8341b468
tree2f856a4cf2ed239581bb3cf8427e30ead161420e
parent35ee2e72c70ceb1e384228e52d985d6c74726122
In r288122, we changed vm_page_unwire() so that it returns a Boolean
indicating whether the page's wire count transitioned to zero.  Use that
return value in zbuf_page_free() rather than checking the wire count.

MFC after: 1 week
sys/net/bpf_zerocopy.c