vdpa/mlx5: prepare virtqueue resource creation

vdpa/mlx5: prepare virtqueue resource creation

Split the virtqs virt-queue resource between
the configuration threads.
Also need pre-created virt-queue resource
after virtq destruction.
This accelerates the LM process and reduces its time by 30%.

Signed-off-by: Li Zhang <lizh@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>