net/iavf: fix null pointer dereference
net/iavf: fix null pointer dereference

Check for memory allocation failure is added to avoid null
pointer dereference.

Fixes: 6bc987ecb860 ("net/iavf: support IPsec inline crypto")
Cc: stable@dpdk.org

Signed-off-by: Weiguo Li <9d74fa1db2adfc67cecdb75bdffcce563fe33719@foxmail.com>
Acked-by: Radu Nicolau <fa459cf59d47c122ba776e9a6f631c862bf44680@intel.com>

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