net/mlx5: improve error on completing table resize

net/mlx5: improve error on completing table resize

If flow template table was created with resizable attribute,
then completing table resize could fail for 2 user-related reasons:

- not all flow rules were yet updated to use the resized table,
- resize was not started.

Both of these were reported with the same error message
i.e., "cannot complete table resize".

Since PMD can distinguish these 2 cases, this patch improves the error
reporting to report these 2 errors separately.

Also, this patch removes redundant __rte_unused on device parameter.

Signed-off-by: Dariusz Sosnowski <dsosnowski@nvidia.com>
Acked-by: Gregory Etelson <getelson@nvidia.com>
Acked-by: Bing Zhao <bingz@nvidia.com>