Implements the Windows Hypervisor Platform accelerator (WHPX) target. Which
acts as a hypervisor accelerator for QEMU on the Windows platform. This enables
QEMU much greater speed over the emulated x86_64 path's that are taken on
Windows today.

1. Adds support for vPartition management.
2. Adds support for vCPU management.
3. Adds support for MMIO/PortIO.
4. Registers the WHPX ACCEL_CLASS.

Signed-off-by: Justin Terry (VM) <juterry@microsoft.com>
Message-Id: <1516655269-1785-4-git-send-email-juterry@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>