sis900: remove unnecessary break after return

Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/sis/sis900.c

@@ -2258,7 +2258,6 @@ static int sis900_set_config(struct net_device *dev, struct ifmap *map)
 		case IF_PORT_100BASEFX: /* 100BaseFx */
                 	/* These Modes are not supported (are they?)*/
 			return -EOPNOTSUPP;
-			break;
 
 		default:
 			return -EINVAL;