cxgb4: Signedness bug in init_one()

The "chip" variable is an enum, and it's treated as unsigned int by GCC
in this context so the error handling isn't triggered.

Fixes: e8d452923a ("cxgb4: clean up init_one")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -5701,7 +5701,7 @@ static int init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	whoami = t4_read_reg(adapter, PL_WHOAMI_A);
 	pci_read_config_word(pdev, PCI_DEVICE_ID, &device_id);
 	chip = t4_get_chip_type(adapter, CHELSIO_PCI_ID_VER(device_id));
-	if (chip < 0) {
+	if ((int)chip < 0) {
 		dev_err(&pdev->dev, "Device %d is not supported\n", device_id);
 		err = chip;
 		goto out_free_adapter;