crypto/ipsec_mb: fix premature dereference
crypto/ipsec_mb: fix premature dereference

This patch removes coverity defect CID 374380:
Null pointer dereferences  (REVERSE_INULL)

Coverity issue: CID 374380
Fixes: 918fd2f1466b ("crypto/ipsec_mb: move aesni_mb PMD")
Cc: stable@dpdk.org

Signed-off-by: Piotr Bronowski <8aa850d50da55b6bd5f690613320d69259cb401b@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk