vDPA/ifcvf: dynamic allocate vq data stores

This commit dynamically allocates the data
stores for the virtqueues based on
virtio_pci_common_cfg.num_queues.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Message-Id: <20230612151420.1019504-2-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>