alteon: acenic: mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 114891 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/alteon/acenic.c

@@ -551,6 +551,7 @@ static int acenic_probe_one(struct pci_dev *pdev,
 			       ap->name);
 			break;
 		}
+		/* Fall through */
 	case PCI_VENDOR_ID_SGI:
 		printk(KERN_INFO "%s: SGI AceNIC ", ap->name);
 		break;