vdpa/mlx5: handle hardware error

vdpa/mlx5: handle hardware error

When hardware error happens, vdpa didn't get such information and leave
driver in silent: working state but no response.

This patch subscribes firmware virtq error event and try to recover max
3 times in 3 seconds, stop virtq if max retry number reached.

When error happens, PMD log in warning level. If failed to recover,
outputs error log. Query virtq statistics to get error counters report.

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