crypto/octeontx: fix freeing after device release

crypto/octeontx: fix freeing after device release

When the PMD is removed, rte_cryptodev_pmd_release_device
is called which frees cryptodev->data, and then tries to free
cryptodev->data->dev_private, which causes the heap use
after free issue.

A temporary pointer is set before the free of cryptodev->data,
which can then be used afterwards to free dev_private.

Fixes: bfe2ae495ee2 ("crypto/octeontx: add PMD skeleton")
Cc: stable@dpdk.org
Reported-by: Zhihong Peng <zhihongx.peng@intel.com>
Signed-off-by: Akhil Goyal <gakhil@marvell.com>