net/hinic: check memory allocations in flow creation

The function rte_zmalloc() could return NULL, the return
value need to be checked.

Fixes: f4ca3fd54c4d ("net/hinic: create and destroy flow director filter")
Cc: stable@dpdk.org
Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>