WHPX fix WHvSetPartitionProperty in PropertyCode

This fixes a breaking change to WHvSetPartitionProperty to pass the 'in'
PropertyCode on function invocation introduced in Windows Insider SDK 17110.
Usage of this indicates the PropertyCode of the opaque PropertyBuffer passed in
on function invocation.

Also fixes the removal of the PropertyCode parameter from the
WHV_PARTITION_PROPERTY struct as it is now passed to the function directly.

Signed-off-by: Justin Terry (VM) <juterry@microsoft.com>
Message-Id: <1521039163-138-3-git-send-email-juterry@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>