Import HyperV Key-Value Pair (KVP) driver and daemon code by Microsoft,
many thanks for their continued support of FreeBSD.

While I'm there, also implement a new build knob, WITHOUT_HYPERV to
disable building and installing of the HyperV utilities when necessary.

The HyperV utilities are only built for i386 and amd64 targets.

This is a stable/10 candidate for inclusion with 10.1-RELEASE.

Submitted by:	Wei Hu <weh microsoft com>
MFC after:	1 week


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271493 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Regen.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271494 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f