regex/mlx5: fix crash on probe failure

regex/mlx5: fix crash on probe failure

The mlx5_regex_pci_probe function allocates a mlx5_regex_priv structure
using rte_zmalloc.

If the allocation fails, the function jumps to the dev_error label in
order to release previously allocated resources in the function.
However, in the dev_error label it attempts to refer to the internal
fields of the priv structure and if its allocation fails (as in this
case) it is actually dereferencing to NULL.

Replace the jump with an error label.

Fixes: 1db6ebd4ef58 ("regex/mlx5: fix crash on initialization failure")
Cc: stable@dpdk.org
Signed-off-by: Michael Baum <michaelba@nvidia.com>
Acked-by: Ori Kam <orika@nvidia.com>