8139too: use true,false for bool variables

This addresses the following coccinelle warning:

drivers/net/ethernet/realtek/8139too.c:981:2-8: WARNING: Assignment of
0/1 to bool variable
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/8139too.c

@@ -978,7 +978,7 @@ static int rtl8139_init_one(struct pci_dev *pdev,
 	    pdev->subsystem_vendor == PCI_VENDOR_ID_ATHEROS &&
 	    pdev->subsystem_device == PCI_DEVICE_ID_REALTEK_8139) {
 		pr_info("OQO Model 2 detected. Forcing PIO\n");
-		use_io = 1;
+		use_io = true;
 	}
 
 	dev = rtl8139_init_board (pdev);