[PATCH] net/mlx5: fix error CQE dumping for vectorized Rx burst

[Matan Azrad]

From: Alexander Kozyrev
> There is a dump file with debug information created for an error CQE to help
> with troubleshooting later.
> It starts with the last CQE, which, presumably is the error CQE.
> But this is only true for the scalar Rx burst routing since we handle CQEs there
> one by one and detect the error immediately.
> For vectorized Rx bursts, we may already move to another CQE when we
> detect the error since we handle CQEs in batches there.
> Go back to the error CQE in this case to dump proper CQE.
> 
> Fixes: 88c0733535 ("net/mlx5: extend Rx completion with error handling")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Alexander Kozyrev <akozyrev at nvidia.com>
Acked-by: Matan Azrad <matan at nvidia.com>