vDPA/ifcvf: remove duplicated assignment to pointer cfg

The assignment to pointer cfg is duplicated, the second assignment
is redundant and can be removed.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Message-Id: <20220704190456.593464-1-colin.i.king@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>