vdpa: introduce config operations for associating ASID to a virtqueue group

This patch introduces a new bus operation to allow the vDPA bus driver
to associate an ASID to a virtqueue group.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Gautam Dawar <gdawar@xilinx.com>
Message-Id: <20220330180436.24644-8-gdawar@xilinx.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>