cxgb4: remove set but not used variable 'spd'

Fixes gcc '-Wunused-but-set-variable' warning:
drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c: In function 'print_port_info':
drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c:5147:14: warning:
 variable 'spd' set but not used [-Wunused-but-set-variable]

variable 'spd' is set but not used since
commit 547fd272 ("cxgb4: Warn if device doesn't have enough PCI bandwidth")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

@@ -5144,17 +5144,9 @@ static void print_port_info(const struct net_device *dev)
 {
 	char buf[80];
 	char *bufp = buf;
-	const char *spd = "";
 	const struct port_info *pi = netdev_priv(dev);
 	const struct adapter *adap = pi->adapter;
 
-	if (adap->params.pci.speed == PCI_EXP_LNKSTA_CLS_2_5GB)
-		spd = " 2.5 GT/s";
-	else if (adap->params.pci.speed == PCI_EXP_LNKSTA_CLS_5_0GB)
-		spd = " 5 GT/s";
-	else if (adap->params.pci.speed == PCI_EXP_LNKSTA_CLS_8_0GB)
-		spd = " 8 GT/s";
-
 	if (pi->link_cfg.pcaps & FW_PORT_CAP32_SPEED_100M)
 		bufp += sprintf(bufp, "100M/");
 	if (pi->link_cfg.pcaps & FW_PORT_CAP32_SPEED_1G)