net/failsafe: fix device freeing

net/failsafe: fix device freeing

The PMD destroy function was calling the release function, which frees
dev->data->dev_private, and then tries to free PRIV(dev)->intr_handle,
which causes the heap use after free issue.

The free can be moved to before the release function is called.

Fixes: d61138d4f0e ("drivers: remove direct access to interrupt handle")
Cc: stable@dpdk.org
Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>