net/virtio: remove useless check on mempool

[ upstream commit 711b07c ]

This .rx_queue_setup devop is called after ethdev already dereferenced
the mempool pointer.
No need to check and we can remove this rte_exit.

Fixes: 48cec29 ("net/virtio: move queue configure code to proper place")

Signed-off-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Jens Freimann <jfreimann@redhat.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

drivers/net/virtio/virtio_rxtx.c

@@ -573,11 +573,6 @@ virtio_dev_rx_queue_setup(struct rte_eth_dev *dev,
 	rxvq = &vq->rxq;
 	rxvq->queue_id = queue_idx;
 	rxvq->mpool = mp;
-	if (rxvq->mpool == NULL) {
-		rte_exit(EXIT_FAILURE,
-			"Cannot allocate mbufs for rx virtqueue");
-	}
-
 	dev->data->rx_queues[queue_idx] = rxvq;
 
 	return 0;