vDPA/ifcvf: alloc the mgmt_dev before the adapter

This commit reverses the order of allocating the
management device and the adapter. So that it would
be possible to move the allocation of the adapter
to dev_add().

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Cc: stable@vger.kernel.org
Message-Id: <20221125145724.1129962-4-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>