vdpa/mlx5: add virtq creation task

vdpa/mlx5: add virtq creation task

The virtq object and all its sub-resources use a lot of
FW commands and can be accelerated by the MT management.
Split the virtqs creation between the configuration threads.
This accelerates the LM process and reduces its time by 20%.

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