vDPA/ifcvf: decouple config space ops from the adapter

This commit decopules the config space ops from the
adapter layer, so these functions can be invoked
once the device is probed.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Cc: stable@vger.kernel.org
Message-Id: <20221125145724.1129962-3-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>