net/ixgbe: reset security context pointer on close

[ upstream commit 848a37cead7bd604d51b5f04507fea3e59e9088e ]

When ixgbe_dev_close() is cleaning up, it does not correctly set
the security_ctx variable to NULL, which will lead to wild pointer.

Fixes: 9a0752f ("net/ixgbe: enable inline IPsec")

Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Acked-by: Haiyue Wang <haiyue.wang@intel.com>

drivers/net/ixgbe/ixgbe_ethdev.c

@@ -3102,6 +3102,7 @@ ixgbe_dev_close(struct rte_eth_dev *dev)
 
 #ifdef RTE_LIBRTE_SECURITY
 	rte_free(dev->security_ctx);
+	dev->security_ctx = NULL;
 #endif
 
 }