qeth: fill netdevice->gso_* attributes accurately

Use QETH_MAX_BUFFER_ELEMENTS(card) instead of constant 16.
Also fill gso_max_segs and gso_min_segs.
Signed-off-by: NEugene Crosser <Eugene.Crosser@ru.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_l3_main.c

@@ -3217,7 +3217,9 @@ static int qeth_l3_setup_netdev(struct qeth_card *card)
 				NETIF_F_HW_VLAN_CTAG_RX |
 				NETIF_F_HW_VLAN_CTAG_FILTER;
 	netif_keep_dst(card->dev);
-	card->dev->gso_max_size = 15 * PAGE_SIZE;
+	card->dev->gso_max_size = (QETH_MAX_BUFFER_ELEMENTS(card) - 1) *
+				  PAGE_SIZE;
+	card->dev->gso_max_segs = (QETH_MAX_BUFFER_ELEMENTS(card) - 1);
 
 	SET_NETDEV_DEV(card->dev, &card->gdev->dev);
 	netif_napi_add(card->dev, &card->napi, qeth_l3_poll, QETH_NAPI_WEIGHT);