net/ice: fix null function pointer call

[ upstream commit a8880ad ]

In case rte_eth_dma_zone_reserve fails in ice_tx_queue_setup
ice_tx_queue_release is called on 0 allocated but not initialized
txq struct.
This may happen on ENOMEM condition, size exhaustion of
memconfig->memzones array as well as some others.

Fixes: edec6dd ("net/ice: remove redundant functions")

Signed-off-by: Tomasz Jonak <tomasz@graphiant.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>

drivers/net/ice/ice_rxtx.c

@@ -1197,7 +1197,8 @@ ice_rx_queue_release(void *rxq)
 		return;
 	}
 
-	q->rx_rel_mbufs(q);
+	if (q->rx_rel_mbufs != NULL)
+		q->rx_rel_mbufs(q);
 	rte_free(q->sw_ring);
 	rte_memzone_free(q->mz);
 	rte_free(q);
@@ -1407,7 +1408,8 @@ ice_tx_queue_release(void *txq)
 		return;
 	}
 
-	q->tx_rel_mbufs(q);
+	if (q->tx_rel_mbufs != NULL)
+		q->tx_rel_mbufs(q);
 	rte_free(q->sw_ring);
 	rte_memzone_free(q->mz);
 	rte_free(q);