eventdev: check allocation in Tx adapter

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

Fixes: a3bbf2e097 ("eventdev: add eth Tx adapter implementation")
Cc: stable@dpdk.org

Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Reviewed-by: Nikhil Rao <nikhil.rao@intel.com>

lib/librte_eventdev/rte_event_eth_tx_adapter.c

@@ -734,6 +734,8 @@ txa_service_queue_add(uint8_t id,
 
 		qdone = rte_zmalloc(txa->mem_name,
 				nb_queues * sizeof(*qdone), 0);
+		if (qdone == NULL)
+			return -ENOMEM;
 		j = 0;
 		for (i = 0; i < nb_queues; i++) {
 			if (txa_service_is_queue_added(txa, eth_dev, i))