vDPA/ifcvf: manage ifcvf_hw in the mgmt_dev

This commit allocates the hw structure in the
management device structure. So the hardware
can be initialized once the management device
is allocated in probe.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Cc: stable@vger.kernel.org
Message-Id: <20221125145724.1129962-10-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>